I agree with only allowing upvoting as _the_ metric to measure the quality of a post or comment.
All posts and comments could be recognized as 'default incoming' content or 'approaching exceptional' content.
+1 for disabling downvoting.
+1 for disabling downvoting.
The instant you let somebody's comment be worth less than neutral value, you've built a mechanized system that makes people feel excluded. That means anybody who wants to can make anybody else feel alienated from this community. Not that I speak from experience.