This blog tends to get much more spam than legitimate comments. Some of it is easy to spot (prescription drugs, porn, etc). Other comments are a little more ambiguous. For example, highly generic comments of admiration about the post, while tempting to consider genuine, are most likely spam. As such, they get deleted with the rest.
So, you have my apologies if I deleted a legitimate comment of yours along the way. For future reference, making the comment clearly refer to the post will make it much more likely to get approved.