The last few years, I've noticed an uptick in "concern trolls" that pretend to support a group or cause while subtly working to undermine it.
LLMs can't make the ultimate judgement call very well, but they can quickly summarize enough information for me to.
So they make somewhat consistent 'generic' posts that do not get remove, but do not really convey any signal on their actual views.
Then in their last 24-48 hours there are more political style posts/concern posts that only stick around while the article/post is getting views. Then replies disappear like they've never happened so you can't tell it's an account that exists wholly to manipulate others that has been doing so for months.
Then quite often after a month or two the accounts disappear totally.
Come to think of it, I bet the original creator is selling these accounts to someone else who is weaponizing them. Or the creator is renting them: build up a supply, rent them out for a purpose, then scrub them and recycle. Work From Home! Make Money Fast! This is one part of why the internet has gone to hell.
I don't have an explanation for why they'd delete the accounts.