The more I think about it, the more I agree with the first. I find it harder to assume good faith when someone blatantly states their strong POV.
This depends--context is everything. For instance, I'm libertarian, but I've edited [[Libertarianism]] because I like to pretend I know something about the subject. In the interest of full disclosure I might mention that I am libertarian, which might unknowingly color my contributions. If I edited a lot about politics (I don't), I might want to outright state, "Here are my biases, if they get in my way let me know and help me improve."
If someone's pushing a POV, you can tell from editing patterns alone. On the other hand, if someone is making valuable, good-faith, albeit biased contributions, it's a lot easier to assume good faith when they say straight out "here's my bias, if it shows in my contributions too much feel free to correct."
Someone says "I am anti-abortion", then proceeds to edit pages pertaining to abortion - what are you going to assume? That he's there to fix typos?
This might surprise you, Steve, but people with a strong interest in something generally have an opinion about it too, and vice versa. People usually edit articles about their own interests, after all.
Abortion in particular is the biggest issue where people's opinions tend to create blind spots. Pro-lifers tend to fail to understand and appreciate abortion-choice arguments while abortion-choicers tend to fail to understand and appreciate pro-life arguments, and no one seems willing to acknowledge that the other side holds their opinions in good faith. It's these blind spots which make it utterly crucial for us as editors to be open with one another about our biases so we can correct one another's mistakes.
For the same reason that we don't allow strong POV usernames (AntiAbortionCrusader etc), shouldn't we discourage stating of POVs on userpages?
Not if we want to get an encyclopedia written according to the neutral point of view.