What level of bullying is acceptable? Not trying to be difficult but this is half the problem. The acceptance that some of this stuff is just 'boys being boys' or the classic, 'it was not serious it was just a bit of fun everybody does it.'
One of the uncomfortable truths is that much of this behaviour is seen by all of us, all the time, to a greater or lesser extent; and nobody did or does anything about it, even if it made us personally uncomfortable. And the action I generally see is either that of people nodding along in concern and then ignoring it. Or the other common reaction when people are called out of 'I don't really do that, or mean it that way, I`m actually a nice guy' combined with 'its all blown out of proportion and people need to not take offence so easily'.
In the end entire population groups, generations of people, even on a small scale-groups of friends, are being told that their behaviour is not acceptable and they are not the wonderful, good people they thought they were. Nobody wants to hear that, and will fight against changing at all costs; leading to long winded explanations, social discourse, and straw man arguments to explain away all levels of poor behaviour. We see it with ***ism, racism, homophobia, xenophobia... pick your -ism/phobia. This is the basic level of human discourse on any of these subjects.