I saw this discussion in the comment section of some post, and it was about what the vote should be used for and how there is no official guideline for how to use it. I thought this was such a good question, that it deserved a post of its own. Related question would be if there should be multiple scores with different meanings, through which posts can be sorted.
Instead of blocking the votes, you could count them differently. But I think this makes more sense as a parameter for federation between instances, not something specific to communities. In your example you could still federate with the people that behave badly in your instace, but assign a low value to their votes.