Abortion and Andrew Sullivan

The folllowing really annoyed me from Andrew Sullivan:

So allowing women to choose to seek an abortion is now a "hard left" position? And encouraging gay couples to have stable relationships is "hard left"? And being deeply concerned about racism and sexism is "hard left"?

Huh? Sullivan is comparing abortion to being "concerned about racism and sexim." How can you compare the two? The former involves destroying a developing human life (and yes the unborn baby IS a human). The other involves an unreasonable bigoted denial of the dignity of another human being. In fact, one can easily make the point that if one is to be against racism and sexim, then the logical conclusion is that they should also be against abortion.

I know plenty of people who recognize the evil of abortion AND also support many "progressive" causes such as gay marriage. Why does Sullivan feel the need to conflate the various issues?