Sexism. The sort that my feminist friends never complain about but that is very likely at the root of the much more egregious forms of sexism that they DO complain about.
I don't really care that no one helped a man fight off a woman half his size, to be honest. The problem is that this generalizes. People don't help men. Whether it's domestic violence or a burning building, people will generally leave men to fend for themselves (and, typically, die). Most men accept this (Christopher Hitchens has this bit about how we men know that we're essentially worthless, evolutionarily), but it's still pretty unfortunate.
A very real problem. Women used to be grouped with children, legally, in many Western cultures. As they've come to acquire the legal freedoms and constraints of men/adults, they've yet to acquire the same social and moral responsibilities. It creates pockets, such as the one videoed, where some awful women can act like children and not suffer the consequences any adult would for doing so.