The reason it seems like more posts are getting deleted now is possibly that deleted posts are visible now. A few days ago I wondered if deleting your own posts is some sort of a new "trend", just because I saw quiet a lot of them.

Apart from that, what is the difference between editing and deleting?

Of course, if only one part of your post is badly offtopic editing would be a better solution, but there is no reason to complain about deleting fully off-topic posts if you ask me.