TF2 is not the kind of game where we should be taking compromises with botters as the developers seem to be withdrawing from the project entirely. So it’s best the keep the place tidy and leave the community with the tools to moderate itself.
I've been erroneously banned from CS2 twice, with no reason given. Both times I've been unbanned after appealing. I have no doubt if I were active on t2 they would have banned me. This only happened once I started using linux too, particularly when I started using dev versions of software.
I think there's a large crossover of stolen accounts and accounts that are used for botting. Furthermore, there's basically nothing (that I'm aware of) stopping you from making a bajillion gmail accounts and I'm sure the process could be fairly simply automated.
Gmail accounts need a phone number nowadays (at least when connecting from Europe). I dunno how it is in other countries. Here SIM cards can be bought for a few €, but making millions of bot accounts would add up. But maybe there are VOIP services that allow creating numbers easily.