Comments from feedback form - "What do you think of this page..."
AFAIU, there is a very short list of things that will get removed from comments pages, and an even shorter list of things that will get you banned. These aren't talk pages, they're comments pages for all the trolls on the net to blast with whatever crap they want;).
The List, as I understand it:
1) Linking to an external non-WMF site (link removed, post can sometimes remain)
2) Personal attacks against non-public people (ie, famous people don't count), usually other commenters, that are sufficiently bad to warrant action (this is judged on a per-post basis, and different admins will make different calls)
3) Clearly libellous statements against public figures. (post deleted)
4) Copyright infringement (post deleted, warning issued on user talk page, possible ban in repeated)
5) Death threats, that are clearly not a joke (local ban, likely global ban, possibly alert WMF, possible referral to local authorities if deemed necessary)
6) Serious sounding suicide notes/threats (always alert WMF, always constant local authorities)
7) Advertising (insta-ban)
If Turtle's comment violated any of those, it would be number 2. Everyone has a different threshold for what constitutes a personal attack. Personally I'd be inclined to leave his post, since while it's angry, it's somewhat humorous as well.
I would hope that threats of physical harm are lumped in with death threats, and that humor doesn't end up playing too big a role in any such administrative decision.
It's not so much a question of the existence of a threat as it is the seriousness of the threat. Paraphrased: "I'm going to make a giant wooden hand, cover it in pubic hair, and then push it over on you at your doorstep" isn't the most serious sounding threat in the world.
Here's a serious sounding threat, as an example: "I work at an ISP. I'm going to use your IP to hunt down your RL name and address. I'm then going to go your house in the middle of the night and make sure you're home. Then I'm going to bar all the doors. Then I'm going to toss a firebomb through a window. Then I'm going to sit on your lawn and laugh while you scream."
That's a far more serious sounding threat, because that's realistic enough that even if the author of the threat has no intention of carrying it out, it may well still cause angst to the recipient of the threat. And that's the real test. Is the threat of a type that might cause real worry to the recipient, or is it just part of a trolling flamewar? There's a difference between the two, and they should be treated differently.
And indeed, "humorous" is not part of the test of what's allowable and what's not. I was thinking about "seriousness", but wrote "humour" due to the fact that there is a bit of crossover between the two concepts in my mind (ie, a post wouldn't be funny if it contains a serious threat).