The issue is procedural. HN threads are for conversation. Showing up with a bullhorn and blasting everybody over and over with regurgitated rhetoric and whole-cloth fantasy is not conversation. The problem would be the same if the content were the opposite.
Channel-flooding HN and treating it as a platform for a campaign—imaginary or not—goes completely against the intent of the site. Liking or disliking the cause is beside the point. I happen to partly agree with it; I have for years. It doesn't matter.
1. I suppose I should add that at the extremes, some views can run into difficulty on HN, though not because we personally disagree with them. But we're nowhere near that in this case.