I suspect they're building up "influence" one like at a time, so they can pull on threads that are useful at some point in the future. It's fake attention directed at you.
I.E. You happen to say something that aligns well with their client's narrative... you get a like, which encourages you to say more things like that.
This is almost the exact inverse of the way Fox/CNN push narratives disguised as "news" by cherry picking facts and fudging a bit.