Some of us need our thoughts clarified by the community.
In any case, I find that learning happens in an atmosphere of uncertainty, humility and exploration. Doubt, thus, is a valuable commodity in any community which encourages learning, and I'd like to believe HN is one of them.
If you respect people, then their opinions tell you things about the search space in which they live. Heck, even if you don't respect people it at least tells you nsomething about how widely known a particular thing is within comparable sections of society.
There are, potentially, some good arguments for filtering your information to keep newbies out of higher level discussion where people are trying to make progress on a problem - but in the context here it seems to me at the moment that you're just being somewhat mean; I don't see what you hope to gain other than to make someone feel bad.
Then why comment? If you have nothing to input from either side. Doubt is not a valuable commodity.