I do not believe one can really be politically neutral. One can be blind to their political inclinations, but what would being neutral even mean? Everyone has their views and values.
“Politically neutral" is a phrase used to distance oneself from the largely American habit of slotting one's values into the red vs. blue dichotomy. One can't be truly politically neutral, as you say, given that politics is a system of dealing with others and not an electric charge. However, it's a phrase that is easier to invoke just as it’s easier to describe oneself as an atheist rather than an agnostic when explaining why one would not believe in God.
Thanks for the comment, I guess it could be seen like that. I still think that being ”politically neutral” is more like being disinterested in politics and/or lacking introspection.