In an answer to the question "Why does the left side with the Palestinians?", one user wrote within their answer
This question is more often than not answered by right wingers, which unfortunately means misrepresentation of the views of left wing people, Palestinians and Israelis to fit right wing prejudices and biases. I have no idea why right wing people so often feel the need to speak on behalf of Left wing people.
and in response to a comment about this, said
Yes, to be honest I would. I don't think that you can really expect an honest or fair representation of left wing people's views from somebody who holds opposing views. Far too often it just results in straw manning the left. I'm sure there are some right wing folks out there who are very well informed about the positions of the left, but simply disagree, and are capable of accurately describing their positions. In reality its quite rare though, isn't it? More often than not resulting in a ridiculous straw man argument a la Fox News (Bernie Sanders wants to turn America into Venezuela!).
I think this is a dangerous precedent. We should not be discouraging people from answering based on what their political persuasion is.
The Code of Conduct mentions the following
We don’t tolerate any language likely to offend or alienate people based on race, gender, sexual orientation, or religion — and those are just a few examples. When in doubt, just don’t.
This includes, but isn’t limited to: bullying, intimidation, vulgar language, direct or indirect threats, sexually suggestive remarks, patterns of inappropriate social contact, and sustained disruptions of discussion.
And discouraging the participation of people based on their political persuasion goes against this.
From a practical point of view, I think that both left-wingers and right-wingers may have biases, albeit different ones, on a question about left-wingers - but that discouraging right-wingers from answering will give result in a worse overall set of answers than if we don't discourage them.
Please note that I'm not meaning to be a free speech fundamentalist here - I'm all in favour of moderating content when there's behaviour that violates stack exchange's rules, and have repeatedly complained about such content on this stack exchange.
I tried flagging the answer, rather than raising it on meta, but it was declined.