There is nothing wrong with a political argument. (It would be a very narrow minded view on business building and IT, if you'd think of them as apolitical.)
This isn't naively denying the political for the supposedly non-political—of course there are politics in everything. It's about the limitations of the internet forum as a medium. We can't have both flamewars and stay interesting, and the mandate of the site is to try to stay interesting. Flames are lame.
Re "business building and IT", I suppose I should add that HN is absolutely not just about business and technology—never has been and never will be, as long as I have a say.
> for what I can only think are ideological reasons
That perception tends to be in the eye of the beholder, in the sense that people of all ideological commitments see HN as being censored in favor of the opposite side, in proportion to the strength of their own feeling. I've written about this a bunch: