I can't link to the thread since it's been deleted, but I do have a screenshot.
Now, I don't know anything about patents, or if the patent in question even affects Danbooru. But, I'm not finding anything wrong with the OP expressing his concern, and certainly do not see anything that warrants its out-right deletion.
Maybe the thread was deleted because the OP changed his thread title to "delete delete" and replaced his thread's body with an apologetic message after seeing Log's reply. But even so, I don't think that would justify it.
If the thread was off-topic, or if it lost its meaning due to the original content being edited-out (which I attribute to Log's rudeness), why not just have it locked instead?
Any thoughts on this?
Updated by 葉月