"First of all, I don't know about you, but I don't come to HN and try to have a somewhat intelligent conversation just to be called stupid for expressing an opinion."
He didn't call you stupid for expressing an opinion, he called that particular view stupid.
Saying that a particular view is stupid without offering any additional information or another viewpoint is... well...
This isn't 7th grade — come up with another word that really means what you want to say. There are a lot of ways to disagree with someone and/or an idea without the derogatory language.
He didn't call you stupid for expressing an opinion, he called that particular view stupid.