That's simply not true. minimaxir just linked to hundreds of Twitter results (as recent as yesterday) of you favoriting and positively commenting on tweets from companies that are explicitly asking for upvotes on their products. I also learned that Product Hunt does this because I've heard/read you specifically mention it in interviews, saying "it grows the site."
https://twitter.com/search?q=product%20hunt%20upvote&src=typ...