It's like the difference between disbelief and belief regarding deities. Antonyms are just oppositely defined words, as indicated by the use of a negative prefix. Thus, "misunderstanding" is simply an error in understanding, as indicated by the prefix "mis-". The word does not imply an understanding of other things.

It's generally a mistake to try to make them anything other than that, I think.

One can be irreverent without any reverence at all. The word, itself, implies that. Just as "atheism" does not indicate a belief in anything. It is simply the absence of belief in deities or "theism."

Sometimes, I keep my mouth shut. Like when I'm invited over for a Christmas party or a Passover seder. When in Rome, I am respectful.

When I am in an internet forum specifically created to allow for uninhibited discussion of religion, a web forum one must voluntarily seek and of one's own volition venture, I discuss religion. Uninhibited.

It's surprisingly sensible when you sit down and think about it, but there's always at least one person who can't seem to wrap their head around it.

As you say, though, on a forum for the open discussion of religion, one need not hide one's irreverence with regard to religion. Open discussion allows for the disputing of religious belief. And so, here we are.