5?! Those are all pretty serious safety issues, fortunately I haven't seen many examples of any of these on the site, and definitely not by one person. We may be using different definitions:
For instance, for spamming I don't mean posting a lot, I mean intentional actions, often using auto-posting tools or bots, for some purpose such as DOS, promoting scams, chasing genuine users away from a service, inflating views and back-linking, etc. Fortunately most of that should be handled by the forum management tools and it is difficult to do something like that here because I don't think you can auto-post, so it would need to manual, which is a lot of effort for the small reach of a niche sub.
Credible threats, doxing, stalking, I haven't seen any of these and I have a hard time believing the mods would not shut those behaviors down and ban someone immediately. Especially stalking - although that can be tricky to stop if the person is using alt accounts to bypass blocks and bans or if they manage to find their target on other platforms as well.
Hate-speech sadly is probably the most common of these on the site, but people are good about reporting it when it happens and the mods have always been responsive to it and shut it down.
There has been some examples of character assassination on this sub over the years, but I can't think of anything recent. There was one about Damo Mitchell awhile back, definitely some posts along those lines during the "additional baked-goods" era. Those are usually very intense targeted attacks motivated by revenge towards some some person, on here it usually seems to be towards a master or public figure by an ex-student.
I haven't seen any significant trolling on this sub, at least since I have been lurking, trolls are generally not invested in the content they target and rather involve themselves simply to create chaos and sow division, often using sensitive topics, rage-bait and trigger words to incite flame wars. It's pretty easy to spot and I can't see the mods not acting on it if it were to happen on the sub.