The reason that 'interesting' threads on these forums get deleted is because members lose their cool and their focus, usually targeting other people or completely de-railing a topic.
It's nopony in particular's fault, usually; the threads just get really heated.
It was really disheartening to just arrive here and find people being so close minded, dismissive and ignorant. I have to say Drugs + MLP was the thing I was most looking forward to discussing. I hope it's not all like this....