It's fine not to know something, but the threshold to comment should be slightly higher than that; a quick Internet search shouldn't already answer your question / remark.
If I'm not careful I start writing an answer to these, only to realize that I've already done so for the same remark several times already. At that point I just dismiss my comment and downvote instead.
I think we're kind of missing a HN FAQ which we could assume is common knowledge. Obviously I'm talking about technical topic where there is a clear answer.