Note that word 'primarily'. It is the important distinction here.
Occasionally commenting on a political issue isn't a problem as long as you do it civilly; some overlap with political topics is unavoidable. But when political battles become the thing you're primarily using HN comments for, that's when it becomes abusive, regardless of which politics.
HN's purpose is the gratification of intellectual curiosity. We can't be that and be a political battlefield at the same time, so we need to draw the line somewhere. The 'primarily' test turns out to be a good place to draw the line.
(There's a separate question of what kind of comments people post when they do turn to politics. To the extent that an account does political flaming as opposed to thoughtful discussion, we adjust the line in favor of more moderation.)
"HN's purpose is the gratification of intellectual curiosity. We can't be that and be a political battlefield at the same time"
Incorrect - that's what communication is entirely about. And communication is what you're destroying.
"Note that word 'primarily'. It is the important distinction here."
No, the distinction is "political/ideological battle. That's destructive of what the site is for," If it's destructive to the site why is this entire thread about Rod Vagg here? It's entirely political and has nothing to do with technical merits of Node.js, at all. Every last bit of it is 100% internal politics, and as you state, this site isn't the place for it.
If you're capable of actually living up to your "This isn't the place for political/ideological battles" then this entire thread needs to be purged from the site.
Then why is this entire thread and subject here? It's entirely political and ideological.