Why are threads deleted instead of just locked?

Hey, sorry I didn't notice this post the other day (been busy with other things).

Posts left up and locked are usually handled that way because even there's something wrong with it there is value to us and/or the community by keeping it visible. We tend to want to leave it visible if it had a lot of discussion going on, allowing those involved to refer to the posts in there still (because with a deleted thread only mods and the OP can see it), or it can be a example to help people post properly. Deleting also feels bad to posters, so locking can often have a positive impact as opposed to deleting.

If we delete something it's because it's a direct violation of the rules, and it's harmful to leave up even if there was a discussion going on still. We try to get in front of things and remove these posts immediately before a discussion starts, but we can't always and sometimes that leads to us leaving it up locked.