I don't mind if a blog doesn't have comments enabled or turns them off after a while. What is frustrating is when a blog has open comments but the author doesn't respond to them. Especially when there are questions. That's not only rude, but shows the author doesn't care about their audience. (There are a lot of big bloggers that do this. If it wasn't for their readers they wouldn't be big, but that point seems to go over their heads.) If a reader is going to spend (waste, in this case) their time commenting on a blog and the author can't be bothered to respond they should turn off the comments.