We do not have to personally agree with anyone's upvoting decisions (i.e. whales upvoting themselves or anyone upvoting poor quality content), but that is the beauty of Steemit. We all have the freedom to operate in the Steemian universe as we see fit.

Ideally, quality content will be rewarded regardless of a person's status - minnow, dolphin, or whale. But as you build influence (and the whales have the most influence), you have more freedom and more responsibility in how that influence is used.