Maybe not. Often when a post appears on the main home feed, people will upvote or downvote based on that post in isolation rather than in the context of its sub-community - because the all the posts are from different sub-communities, and it isn't obvious which is from where.

That was a common attitude on Reddit. Mods are needed to determine if things fit a community and abide by the rules. Readers may not even know what community they are in and will upvote things they enjoy. They generally don't upvote based on fit to community.

I didn't notice the comm until it was point out. I don't mind it too much but if it is too lax, people who curate their feed a lot will be seeing more spam.