It's not inappropriate, I'm seriously trying to get an idea of your approach here. You've got 3 posts, all somewhat confrontational. I'll grant you that it's a little more saucy than the typical, "Hi I'm Bob and I ride bikes," but it seems you're itching for an argument. We try to keep it civil. I'm all for disagreements but we want to be mostly civil.
Personally I don't like riding in the mud because it's a mess. I don't think people should, but I honestly don't hold it against people if they do. It's not my place to judge others. I used to do it 2 years ago and it fucked up all my bearings and made my bike a total mess. I'm sure it wasn't good for the trails either but like you say the parks are fine at the end of the day.
I do think you should avoid the trails if it's rained the whole week. But if it's mostly dry or even so-so and it rains, hey it's your choice. To me it's not an "us vs. them" situation. If you feel ok with it, again, it's not my place to judge. But if you have to chip the mud off with a butter knife after you ride, I'm not sure that's a good thing.
To that end, it also hurts the cause because every biker covered head-to-toe in mud makes us all look like we don't care. Since we go through these cycles of access battles, being seen as the guys who ride in the messy trails isn't a good thing.
On the other hand, there are some that cry wolf when it sprinkles and I think they're over the top.
On Sunday I'll be on the other side of the world so I haven't given it a thought.