And shortness in an argumentation is a mark of elegance, not of AI writing(which, just as an aside, is usually verbose? Where are you getting two-word replies from AIs?)
You need to be more careful with scope regarding words like "exist".
Asking me to prove something to someone in particular is a fool's errant. If you close your eyes, I cannot prove to you that you are able to see the sun.
But sure, if the perspective of bdangpublic is the measure of truth in this argument, then I claim that they exist instead. I should like to see them disprove their own existence to themselves. And simply arguing that I cannot be certain of their existence will not hold, since my perception is evidently irrelevant.
Sources can include people you've never met, have no reason to lie, and happened to be in an opportune position to contribute to the sort of lowercase p proofs that you need.
If we can fix social media there can be many such people. If not, there will be necessarily fewer, and they'll have to be replaced by people for whom addressing the public with new information is their job. The latter sort are high value targets for corruption. As long as they're worried about keeping that job, they have to also worry about who they upset with their information. You're necessarily going to get weaker lowercase-p proofs from such people.
That's not to say that we'll have no tools for keeping power in check, but we will have fewer, which means their abuses will be more frequent and more severe.
On every day of the week ending in 'y'. People did know that before social media I'm pretty sure, and they still do.
You want to know whether something is true? Stop taking peoples word, demand capital 'P' Proof, and infer exclusively based on that proof.