Another reason sexism is not seen as bad as racism, is because sexism is a much older, much deeper seated hatred than racism is. Racism's really only half a millenia old while sexism has existed for at least 4 and possibly as many as 8. Hell of a difference. It's going to take much, much longer to root it out.
Also on a purely practical note, the bald, essentialist racism that used to be the norm in the west, is no longer needed as an ideology. It was invented to justify what was possibly the cruellest and most vicious form of slavery the planet has ever seen, but that slave trade no longer exists so we don't need the ideology that underpinned it. We've developed other racist ideologies instead to justify the worldwide exploitation of the developing world by the developed world and the systemic disadvantage black people have in terms of jobs, housing, health etc. in Europe and America (and to avoid paying reparations of course) but it's not essentialist racism IYSWIM. It is simply no longer acceptable among educated people to opine that black people are inherently more stupid/ less moral/ more criminal/ less godly/ insert racist stereotype here than white people. The establishment doesn't need racism any more so it's happy to pretend to be against it.
But men's unfair advantage vis a vis women - well, that's still needed. Our subordinate place, economically, socially, psychologically, is still needed; our unpaid labour is still needed. If all the free labour women do stopped tomorrow, capitalism would collapse; maybe not tomorrow, but very soon. If women stopped doing all the social networking, all the emotional work of relationships... well, I'm not sure what would happen, but it would be the end of relationships as we know them. Men would have to behave differently - and frankly, on the whole they don't want to. Who would? It's nice having an unfair advantage, you have to be a really nice person to voluntarily give that up and most of us aren't that nice, we're just ordinary.