It's virtually true that one's voice is what counts but not entirely. Just like what is written in the bible,

Ecclesiastes 9:16 (NIV) So I said, "Wisdom is better than strength." But the poor man's wisdom is despised, and his words are no longer heeded.

I like your sense of homour. It becomes a problem and an act of greed if one doesn't upvote other people's work that one likes. At least, it's a community and community isn't made of just one person.