It limits visibility for others, but does not prevent the same type of content from popping up for the user who downvoted it.

Further, there is no "karma", so you won't see less content from users who have received many downvotes.

Because we still want the votes to represent what the people who actually like this community would find useful and weed out spammers. You are not a vegan, you are not going to like these memes, this isn't for you. This is a community running on a dell in my closet that was put up as a joke for my friends. The only reason it goes to everyone's all feed is because 70 people like it and subscribed to it. If this is not for you, and you are browsing all new, then just block the comm, that is the intent of the software and being censorship-resistant.

When mad losers downvote everything on the site it makes it is just spam.