In some sense I agree with you* but trending has a dual purpose. One is to show "interesting" content that people might want to view or read, and the other is to show what voters are awarding with payouts. If a lot of payouts are going to these, then why shouldn't that be considered "trending"?
Probably we should have separate lists, but it always starts to get unclear when you try to decide what is "good" or "worthy" of some sort of treatment and what is not. According to whom?
* and this is why I personally vote for the burnposts and comments only after 3 days, so they don't show up as much on Trending. But I can't stop other people from voting earlier, so again, if people are voting, then it really is "trending" isn't it?