I think his age/perspective needs to be taken into consideration with some of the tone/approach he has ... He's got grandchildren now, after all (which in my mind puts him the same age as my FIL and dad) -- and from what I've seen, that generation of men seldom were very involved in childcare. He describes becoming more involved and what an awakening that was for him as a parent (and it's clear that he had a much closer relationship from the beginning with that child and subsequent children). I honestly think they stumbled onto AP and what they've done to try to popularize it, based on how successful it was for them, is a really good thing.
My parents were able to basically both SAHP (they were self-employed, often both home or if one was gone the other was the caregiver) -- so my dad is comfortable with parenting in a pretty egalitarian fashion and remembers a lot about when we were little/babies - we spent a lot of time with him. But dh's dad doesn't remember much about his kids' childhood 'til they were in elementary school. He loves them dearly but it wasn't his responsibility 'til they were older.

Unfortunately I think there are still fathers like that out there, missing out on some really special time with their children. If nothing else, Dr. Sears' description of the awakening he had should help those fathers realize that they should become more involved (beyond appreciating their wives, actually participating in parenting when their children are infants).
I just read the Discipline Book myself and can't recall the section discussed above -- I'm not sure where it was, I should go reread it. I like to think I'm pretty sensitive to gender/orientation bias and I think I thought "Hmmm" at a few points during the book, but am pretty comfortable throwing that sort of thing out and focusing on what IS workable/"right" for me .... I think he's in a position where his books are kind of an "introduction" to AP parenting philosophies for many families, and so some of the old stuff does get dragged in and discussed (because that's the perspective that one or more of those parents is bringing into the parenting discussion, and it needs to be addressed to make them more comfortable). Not necessarily that *Sears* supports it, but that he realizes he needs to allow people a comfort level to build up to being comfortable with AP completely, KWIM?
In terms of Christians being anti-gay -- I'm Christian, my uncle is gay and several of my close friends are too. I don't think that Christians are inherently anti-gay; some are, some aren't. To assume that we are, is a disservice to a lot of folks out there who *aren't* bigoted against homosexuality.