Well the BayFormers weapons were shown to do that too in the Dark of the Moon.
And at least the Helicopter one in the 1st one had shields (that were later gone when Sabot rounds were employed.)
Tripods have size but the Tfs have mavuveurability and some have total control over all things mechanical. Plus if Sam Witwicky has a cold, the Tripods are f***ed.
With disease the tripods lose of course, but they could probably wipe out the Autobots before that happens. Their shields are basically impenetrable, the humans used missile barrages, javelins, etc. and they had absolutely no effect.
Even without force fields, they have numbers on their side (1000s of them vs. a dozen or so Autobots). Transformers have been beaten with automatic rifles, grenades, etc. the tripods took on the US army and came out on top.
This should then have been called "Autobots vs Tripods."
Cause if the combined might of the Decepticons and Autobots turned up, the Tripods would be fubared.
One shielded decepticon took out an entire airbase and went about his day.
G1 Megatron in the comics took the equivalent of the abuse that the tripods took in the biggest battle they had singlehandedly, laughed, and went back into his fortress.
And Unicron would have eaten Mars and destroyed all the tripods just by willing it from millions of miles away in space.
So, without biological weapons, with it being a handful of Autobots only, no decepticons against the other side, with it being Bay Formers in particular, we can see that it is TFs at their lowest possible denominator vs entire planet full of uninhibited devastating attack force.