Also even when some are trolling, the up/down vote will not gain/lose attention for the troll. Trolls love attention.

The lack of karma means participation is there not whether it is a troll or regular.

Unless it is spam, almost no one is punished/rewarded for participating.

On Lemmy there is disincentive to troll right? If you're being too much of a troll you might get thrown out of your instance for making it look bad. Unless you selfhost of course. I'm not sure why botspam from selfhosted lemmy's is not a bigger problem to be honest. You can deferate them but it's easy to make new ones.