I understand you calling it unsubstantive (so I guess I were right in that we're not allowed to post opinions here), but it did contain more information than that:

Obviously there's people who liked to use HotelTonight, who don't want to give money to AirBnb. These people are now in a predicament and that's the other information he was communicating.

Now, I don't want to disrespect the work you do here, but I don't see any reason why simple downvotes and a low ranking in the comments section wouldn't have sufficed for this comment.

(From your reply though I gather this isn't the first time you interacted with this individual. So, do you think it's possible you'r not judging objectively here?)

I don’t think that’s true, but merely expressing an opinion without providing some form of justification or argument isn’t really something that is viewed favorably around here.

I’m just a user on this site, but I tend to prefer to read comments that go beyond one liners in the vein of “something sucks”. To me this is a place to express thoughts that further the discussion, not to express one’s emotions necessarily. Just my two cents.

It's certainly possible to make the point that someone who likes HotelTonight might not like Airbnb. It just needs to be done without breaking the site guidelines. That's easy enough, so shouldn't be an issue. And it doesn't mean "we're not allowed to post opinions here". That's what people do all day on HN!