I'd ask you for evidence that these people are actually trans to begin with.
Which people?
You've made definitive claims about what being a trap means. You've made definitive claims about what being a trans person means. You have provided zero evidence to substantiate these claims. You haven't even provided a speculative theoretical basis to substantiate these claims beyond your opinion. You have very obviously never actually spoken to a trans person about this. The fact that you feel entitled not only to decide who is and is not trans, but to demand that your views on who is and isn't trans be taken as presumed gospel until I "prove" you wrong is pretty damn insulting.
Let me clarify something. I don't actually care about any particular 4chan thread. I don't care whether or not the people who show up on any particular 4chan thread are actually trans or not. Firstly, because it's still insulting and queerphobic to refer to cis male fem or GNC people as traps. The word is not a nice word, it fundamentally implies deceit or fakeness, and assumes a predatory or aggressive motive behind gender non-conformity, which has implications for all GNC people (including trans and non-binary people). Cis men who cross dress or adopt a feminine gender expression are still not trying to predate straight men.
Secondly, a few pages back your argument rested on the idea that everyone described as a trap must personally identify as male, implying that those who refer to others as traps are deeply concerned with respecting the gender identities of GNC people and would
never misgender someone. Except it now turns out that you've decided that noone who shows their genitals on the internet could ever possibly be trans, without providing evidence and without consulting a single trans person before making this claim, so really what you meant when you claimed there was a clear distinction between traps and trans people was that you get to decide what that distinction is, and it doesn't actually matter how people identify because that's something you get to decide for them.
It's not hard to find examples of trans people being called traps. Just head on over to pornhub and type the word trap into the searchbar. But again, that's not really the point. The word is an ugly word which describes an ugly idea and using it has unpleasant implications for how you view all GNC people. If you don't want to carry those implications, stop using it. There are better, more accurate, more generous words for any person you might be tempted to call a "trap".