In newer versions of Lemmy you can quickly check someone's modlog:

That helps from time to time to see who you're dealing with

I honestly think it's kinda lame since you can't see who is just being a troll.

That's exactly why it isn't a thing on Lemmy. Not because knowing who is a troll of a bad thing but because it is a terrible measure of that. Karma systems, like Reddit's are far too easy to game in order to lend a false sense of legitimacy to statements associated with an account (or try to make a legitimate account appear illegitimate) in order to manipulate people. Propagandists and other bad actors love karma systems because of this.