I often wonder about this myself when I see people's posts on here about very severe storms. While I realize that people's hopes on a website aren't going to change where a storm hits, everyone is a hardass about tornadoes until one destroys their house or worse.
I also think a lot of the people who root for tornadoes live in buildings they don't own... apartments, rentals, etc. That or they just don't think it can happen to them and don't much care if it happens to anyone else.