I would always leave the answer pinned to the top. The nature of Q&A here has always been asker centered and there's always been a disconnect if not a weird animosity between askers and answerers. I've always tried hard to be a bit of both. Of course answerers would want the top answer to bubble up to the top. But that's just yet another way of saying that the person asking the question is wrong.
I don't expect this post will garner many likes, but at least you're hopefully reflecting on whether your pride is telling you that the animus you feel toward the person making seemingly arbitrary button clicks not in your favor is a problem with the system or a problem with yourself.
Citing no evidence, I think I've got one of the worst answer-to-accept ratios of anybody who hasn't been banned from the site several times (I think I've only been banned once) so I should probably like this, but it's yet another way to crap on the user.
The reasoning on the technical sites is rather sound. Versions change etc... But the Truth doesn't change. Here, there's no real conflict. There's no reason to treat the accepted answer as anything except the defacto answer, more scholarly gentlemen and women may one day come along and provide a more robust answer but the first, best answer ought to be considered the top answer.