I think some people are confusing Jason Todd the snot-nosed discipline-deficient Robin with Jason Todd the Nightwing-aged, willing to kill, super-strategist, took Batman to a stalemate and even took over access to some of Batman's weapons Red Hood.
It is like comparing Lance Armstrong as a 14 yr old kid riding a bicycle on a paper-run to Lance Armstrong as an adult winning the Tour de france time after time like it was pop-candy!
Now, the Punisher is good. No, he is great. In weapons combat he is definitely top-tier. No doubt about that. In hand to hand combat he is also very profecient (although that rarely makes it to print, but when it does it is evident that while Frank isn't Elektra or Iron Fist he is still able to hang with the best whenever necessary). Furthermore, Mr. Castle has an ingenious mind that enables him to come up with the most efficient (and effective) strategy for fulfilling a specific task or objective. Thus, if Frank wants to kill you he WILL kill you.
However, in a debate scenario (in any genre, from comics to geo-political stratagems) it is MANDATORY to look at the other side. Otherwise what happens is myopia sets in, and one only looks at the strengths/advantages of ones character and ignores the (potentially greater strengths of advantages) of the other character (or that the other character has attributes that negate the abilities of your fave character).
Now, here we have the Red Hood (Jason as an adult). The guy is now around Nightwing's age, and he has a major bone to pick. Also realize that even as a Robin his main forte was fighting (as opposed to Dick's acrobatics, and Tim's detective-oriented mind .....mind you, both Dick and Tim can fight like crazy, and someone like Tim even got more stringent fight training, but Jason's 'tinge' was fighting).
Moreover, after he cam back from the dead Jason Todd has had a major chip on his shoulder (hence his use of the moniker 'Red Hood,' since that is what the Joker used to call himself, and it is the Joker who killed Todd). As shown in his appearances, he is more than willing to kill. Even going as far as taking out 25 bosses (note: bosses do not just hang out solo) and chopping their heads. Thus he has no remorse when it comes to killing.
Then look at training. Even as a kid, infiltrating a room full of armed trained adults was no big deal. Goodness, any of the Bat-family seem to specialise in taking out large groups of armed people. Some like Batgirl (Cassie), Batman and Nightwing seem to be especially gifted, but even Bat 'cousins' like Huntress can take out a group of armed men (it is just that compared to someone like Batgirl, who can take out an entire BUILDING of trained operatives, Huntress seems to kind of seem dim). Jason Todd, as a kid, could do the whole 'armed group' elimination thing. Thus comparisons with Punisher taking out '24 armed Viet cong' really doesn't hold much water.
Now, we are talking of Jason Todd as an adult (the Red Hood). If as a kid he could do what he could (even though, in Batman's own words, he never really was 'that good'😉 then what could J.T as an adult do?
Also consider that he has faced off against Nightwing, and won. He has faced off against Batman, and stalemated Bats. The fact that the Punisher has taken out 24 guerillas in S.E. Asia really adds up to absolutely nothing here (any member of the Bat family - especially Tim, Dick, Bruce, Cassie ..and Red Hood ...can do that with ease. In fact the way they fight, the more armed men there are the easier it is to take them out due to the confusion). Thus Frank Castle taking out a group of men is a great feat, but (and this is why it is prudent to look at the OTHER character) that feat is totally useless since the other guy can do the same .....and probably do it with their hands tied behind their backs.
As for weaponry. Well, Frank comes loaded. But Jason is also able to come up with orthodox weaponry (eg rifles, RPGs, etc that the Punisher probably has stored in his fridge), special weaponry (eg the mini-gun he was using ....and the Punisher probably made that for him and probably has 100 other miniguns in stores around the globe)
as well as unorthodox weaponry (Red Hood managed to take over Batman's arsenal, replicating and in some ways improving on it .....now, the Punisher hits a brick wall here).
Someone mentioned that the first person to get a headshot wins. True. And everyone knows that the Punisher is a crackshot. However how good of a shot do you think someone who can throw batarangs to flick a switch is? Todd is not some amateur in ranged weapons, and he doesn't have Batman's problems with guns (although with Red Hood's mind, he wouldn't even have to use a gun ....but if he needed to it would be easy).
Then the final thing. Strategy. As said, Frank is no slouch here. While he is mostly shown shooting, the guy is also a thinker. He can plan out a strategy/tactic on the move, and it will be effective (and more often than not brutal). It works.
However Todd (RH) is not some snotty-nosed kid anymore. The guy out-strategized Batman. That is all that really needs to be said about that.
Anyways, someone (DoctorStrongBad) was saying that the Punisher would win this 10/10.
The honest truth is that the Punisher would be lucky to walk out of this one alive.
Why?
Well, because for one he isn't facing off against some trained killer. He is facing off against a killer of trained killers (there is a difference). Thus the Punisher is basically facing off against some like ...well ...himself!
That immediately makes the fight a 5/10 for both.
But it doesn't stop there ......
If Punisher tries direct line-of-fire attacks (eg trying to shoot at the Hood with an M-16, or trying to snipe at him from the roof) that will not work. It wouldn't work against ANY of the Batfamily (from Tim going up through Nightwing, Batgirl and Batman). Actually trying to take such an approach would mean that the Punisher just became a semi-stationary target. Not good against a Batfamily member.
As for bombs and grenades and what not (as someone mentioned that Punisher would be using those), well .....again look at who he is facing off against. Against some Mafia thug it would work. Against some Cambodian death-dealer it would work. It would even work against the '24 Viet Cong' brought up several times. But look at who is the opponent.
Oh, and the Red Hood has no issues with explosives himself.
Anyways, the worst case scenario against the Red Hood is 5/10 (him and Punisher having a draw).
However the end result would most probably be a 8/10 (with the Red Hood winning 8 times out of 10).
And to be honest based on how Red Hood messed with Batman I am tempted to say 10/10 for the Red Hood.
The conclusion is: There is no way the Punisher wins more than 5/10, and there is a great likelihood that the Punisher will indeed only get 2/10, and there is a chance likelihood that the Punisher might even end up with a zero/10!
Against Jason Todd the Robin, Punisher would win.
But against Jason Todd, Red Hood, scourge of Batman and Nightwing .....well, Frank Castle will be lucky if Todd doesn't simply win this 10/10.