Percusso made an interesting comment below, that attacks on men because they are men is "sexist". It's an interesting point, but I'm not sure I agree with it. Prejudiced? Yes. Bigoted? Probably that too. But not actually sexist. Sexism, like racism (and most other "bad" isms) are largely about the combination of prejudice with power.
There are a lot of people who support my definition, but a lot of people who don't. And there's very little to argue definitively that power is a neccessary precondition of racism or sexism, or vice versa. But I think it's very important that we define it as such because it helps distinguish between the dangerous impact that sexism and racism has on people's lives, as opposed to only people's feelings being hurt (which is also no laughing matter, but a less serious designation nonetheless). When people are sexist or racist (or a similar ideology), entire classes of people are subject to being second-class citizens economically, socially, or in terms of physical safety.
This distinction is more than merely semantics, because it separates "being a prejudiced jerk who we shouldn't imitate" from "being a prejudiced jerk who can cause unbelievable pain and suffering to entire groups of people--and we especially shouldn't imitate him." While working against prejudice of all kinds is important, preserving the distinction of prejudice and power is important to understanding why injustice exists for entire categories of people.