A question about moved threads

Lately I have been seeing more and more moved threads, and considering I can't view them, this might mean that you have a secret trash can of posts. I'm kinda wondering, what reasoning is behind moving these threads, while locking them is fine most of the time? If they contain links to stuff which is inappropriate, then why aren't they simply edited out and locked? Just kinda wondering, as them being moved this way prevents others from learning from those mistakes. That's all.

I remember viewing one before it moved (which I will not go into detail about) which was about something that shouldn't of been discussed in public, and rather done through PM or not discussed at all.

The default behavior when moving topics leaves a redirect behind. If you can click it but it comes up forbidden, then it's linking to the trash and we forgot to get rid of the redirect. There is a trash forum which contains exactly what you'd expect, mostly for IP logging purposes.