OP, while I'm not in any way advocating or excusing rudeness, I think there's a pretty simple explanation for why it happens, if you look at it from the perspective of the regulars on this board....
We average at least 4 threads a week asking for ways to avoid paying for parking at the theme parks. It gets discussed here, at great length, pretty much every single day. Every single thing that could possibly be said on the topic has been said, several times over. The inevitable result when it comes up yet again, is snark, and lots of it. Not saying that that's what we want to have happen, and as moderators we do want people to realize that the question may not be new to them, but it is to the poster, and to be respectful. But, when you're dealing with 'topic fatigue', it happens.
The other thing that's going on here is that most frequent visitors to WDW have had those fun times when they were late for their long-awaited DTD dinner reservation because they had to drive around the DTD lot for an hour, looking for a space.
Or, when they paid the hefty premium to stay at a Disney resort so they'd be close to the theme parks, and then had to drag their exhausted, cranky kids and their exhausted, cranky selves across the entire parking lot at their resort, because the lot was packed full of cars and the only space left was about a mile from their room.
Then they come here, read a post asking if it's OK to stay offsite and park at DTD to avoid paying $14, or if it's OK to stay offsite and park in some resort lot to avoid paying $14, and their blood pressure goes through the roof, remembering all the times they couldn't find parking.
Again, there's no excuse for posters to be rude. But the bottom line is, all of the ways to get out of paying for theme park parking are going to inconvenience someone else, and probably someone who arguably has more right to the parking space than you do. And that's going to get peoples' hackles up.
