Black Adam is slower than Supes, being able to steal his speed without issue isn't indicative of the ability to steal Supes's without issue.
The exact reason Zoom's immune is ambiguous. It SHOULDN'T be ambiguous being it was spelled out plainly as him not being connected to the speed force but from what I understand that contradicts other instances of Flash speed stealing(likely your instance of him draining everyone on Earth was one of their reasons) so all we know is that it has something to do with his time abilities. Just so there's no confusion let me be clear and say that I'm not saying that any specific limits should be placed on Wally's ability. I think that kind of thing should probably be dealt with on a case by case basis for the most part. I'm just saying that I don't think he should be given a blanket pass for it being a guarantee no matter how powerful the opponent.
Never let anyone else define you. Don't be a jerk just to be a jerk, but if you are expressing your true inner feelings and beliefs, or at least trying to express that inner child, and everyone gets pissed off about it, never NEVER apologize for it. Let them think what they want, let them define you in their narrow little minds while they suppress every last piece of them just to keep a friend that never liked them for themselves in the first place.
To answer the thread starter then, no, I don't think it is. There are always going to be characters that have an innate resistance to that kind of thing.
But Jay is also a different entity with very different personal limitations. His heart condidtion for example prevents him from going super luminal for nore than a brief period. Getting his heart rate up to a certain level would cause another heart attack.
Which simply means stealing his speed doesnt pose as great a medical risk. Even in stealing BA's speed to time jump Jay first went and said goodbye to Joan before attempting it. He literally expected doing so to kill him. He also only just exceeded LS long enough to time jump even with that speed steal (where with Supes he was trying to prevent him from catching wally and making himself able to)
During the period he was training Bart he would steal speed and lend it to Bart so as to not put his own health at risk. In fact he used Sleed lend a lot more than steal for that reason.
So with Jay he has to be more cautious in the amount of speed and how quickly he steals it.
it really isn't. Zoom is immune because he doesnt use speed. He has no speed to steal. He moves gast purely because he has a different relative time rate (one that is loose and non conformed). He's not moving thru space so much as moving and time is different for him.
There in lies the limit. Speed steal really shouldnt be enough against anyone who has some degree of power over time.
The likes of Kang, Time Trapper, Waverider, Chronos. Any mage who has demonstrated abilities over time (Dr Strange/Fate, Arion, Tempest, Faust etc) has a work around. Just as any celestial being who has demonstrated the same has (Galactus, anyone with time stone, celestials, some high end new gods), or any scientist who has developed tech to play with time (Brainiacs {1/2/5}, Ultra-Humanite, Dr Doom, Per Degaton)