Moore did not mean that objectivists are literally racists, just that both groups have anti-egalitarian worldviews. If he would have made Rorschach an unlikeable character, he would have played to the central assumptions of objectivism, as opposed to critiquing them. The main point that he attempts to make with the novel, I think, is that the world is far from the cut-and-dry place that heroic fiction makes it out to be. Watchmen serves as a critique of hero-worship more than anything.
That makes it somewhat ironic that the director of the 300 is making the Watchmen film, since 300 was pretty much an ode to hero-worship, but I really don't think Snyder has a strong idealogical position either way. He just wants to put cool stuff on the big screen, and thankfully recognizes that Watchmen is cool largely because of its ideas, if everything he has said so far is to be believed. If the Watchmen film is screwed up, it will probably be the doing of the studio, since they seem to have problems with everything from the amount of sex and violence in Snyder's cut of the film, to the length of it, and
the fact that Veidt is not shown to be an outright villain and subsequently offed by the "heroes".
Luckily, Snyder still has enough cred from 300 to get his way on most things, with the possible exception of the length of the film.