I am inclined to go along with your views about this EtihadBitcoin being an alt-account (or more likely being part of a farmed account) but I doubt it has been sold because the email address was not changed, his account showed "This user recently woke up from a long period of inactivity."
Keeping aside the
account is sold possibility, if this is a farmed account the puppeteer is simply wasting his time using it because of the negative tag attached therefore I would have asked why would he use it even for nefarious purposes but the suggestions in this thread cover several scenarios. In my opinion, those behaviours bring attention to the account and render it even more useless.
You may not be wrong, what's your assumption about that member? I believe such moves are quite strange because a user who hasn't been active on the forum for many years, starts making posts on topics that are part of reputation board. The case is clear, the user who posted there already had full knowledge about that thread.
I think there's chance that the account might be an alt account of someone else who might not have guts to post in that thread from his/her original account. That could be the case I believe because such accounts when wake up after long time start positing in threads like that shows that they already knew about the thread and that's why he/she posted on that thread instead of any other thread.