You explained perfectly well.
Voting seems to be slack at the moment. Most people only get 10% of their followers to vote, if that.
I don't know what causes this reluctance to curate. Maybe it is a concern for voting power, maybe people think their vote isn't worth much anyway, maybe people prefer to keep their voting power for upvoting themselves, maybe people just can't be bothered to curate the people they follow.
Writing a positive comment without a vote is a bit ridiculous, I think. I tend to ignore those who do that.
Thank you @ocrdu. ☺
I think those people should be ignored, too. I got so pissed last night when found another one that I immidiately mute that person straight away. I might be overreacting but such behavior drives me mad.
You are so right on that as well as on the observation that "writing a positive comment without a vote is a bit ridiculous". It really is, not just a bit but a lot. ;)