To add further to the former category: appropriate friendly ribbing or banter definitely fall under the category of basic human dignity or respect.

People cry at weddings. Not because they are sad, but because they are happy (usually). Why cry when you're happy? Studies[1] suggest that crying lowers your defenses. Similar to how salutes and handshakes were ways of demonstrating you weren't armed, you form a lot of social bonds when you are comfortable enough to be defenseless.

Friendly banter is exactly that, on an emotional level. Sure, crying may make me physically less defended, but allowing some friendly coworker banter makes me emotionally less defended. This encourages bonding. it's the difference between laughing at and laughing with.

Targeting someone maliciously is never acceptable. But friendly banter is sometimes not acceptable. Different people have different tolerances. Calling someone a fat worthless piece of garbage. Probably not ok. saying "geez, another donut?" to a coworker may trigger a group laughter (the subject included: "I start my diet tomorrow, i swear!") or it may cause a reaction the exact same way calling them a worthless piece of garbage might. Discussing their weight might make them feel vulnerable in a bonding sort of way, or in a targeted sort of way, you really should know a person before making those kind of comments though.

I had a young colleague who quit recently. He missed our weekly developer meeting (because he was new, and forgot) and when we got back, another colleague said "Yeah, since you weren't at the meeting, we spent the whole time talking about you" in a clearly joking way, trying to include the new guy in the banter. In fact, he said it to 3 different people who missed the meeting (man, a lot of people missed the meeting that week). The guy demanded he not be a part of the "bro culture" and wanted to work remotely full time. The counter was remote 3 days a week, in office 2, and his desk could be on the opposite side of the building. He rejected that. If you were there, it was apparent that he wasn't being bullied. he had moved across the state for a job and was looking for any way to be able to move back home while keeping the job. His goal was not to get dignity and respect, his goal was to get his way. If he wanted dignity and respect (and honestly thought we spent a whole meeting talking about him behind his back), then any of the concessions offered to him should have worked. Everyone on the team tried to include this guy. Treating him with kid gloves really was kinda more segregating than a toxic individual (when its better to just not talk to someone about real problems than risk upsetting them, that's an issue too). The other guys who missed the meeting looked at the clock, said a profanity, then laughed about it.

[1]: http://www.livescience.com/7854-theory-cry.html - "Crying is a highly evolved behavior," said researcher Oren Hasson, an evolutionary biologist at Tel Aviv University in Israel. "My analysis suggests that by blurring vision, tears lower defenses and reliably function as signals of submission, a cry for help, and even in a mutual display of attachment and as a group display of cohesion."