I have downvoted some type of comments here and there, in the past because like you, I didn't find them useful and that's just about it. Also, I'm in full support of going after malicious intents and accounts and abuse as well as they pollute the chain.
I've seen this happening every once in a while. It has an impact on how active some people are on the blockchain, and on their sentiments. And that's especially hard for newcomers
I've been seeing it a lot and I won't really think it's good, I think we should find a way to mitigate it. We should go after outright abuse but limit other forms of downvotes. I'd rather not support a person than downvote them. I think when you constantly do this, they'll get the memo
That what I generally prefer to do.