The problem with altering existing characters this way is that in doing so they cease to be the characters anymore. When it comes to comic books, most super heroes have spent a lot of time rescueing their love interest of the moment, flirting, and everything else people do. What's more we've also been looking inside the heads of these guys and girls, oftentimes quite literally with thought bubbles, and even following them home and seeing what they do when they are not acting as super heroes. As a result, taking a long running character and saying "this character is now gay" when there has been no indication of that does not work. Nor does changing a lot of these characters to other kinds of minorities, especially if the character in question has already stepped out as a member of the majority in one way or another and attempted to promote tolerance in the past... and other things. I mean we've followed Spider Man around long enough where it's not like they can just suddenly have him be black and treat it like it's still the same character, or it was always that way and we just didn't notice.
I understand the political sentiments of the left wing, but I disagree with them. It's not an EASY path to slowly intergrate minority groups into established media continuity, but to do it RIGHT and ever have it truely accepted that's what you need to do. Of course I also firmly believe that any kind of intentional intergration, affirmitive action, or political correctness is wrong. Rather things change slowly, as society does. Spread the ideas, and if they catch on for real, then the rest will slowly change to match those ideas on it's own without any kind of concentrated effort being nessicary. The very arguement about resistance making this nessicary, is why it's a bad idea, because that resistance simply means the level of tolerance hasn't arrived yet. Trying to force yourselves down other people's throats makes you as bad as those you claim to be opposing.
When it comes to things like gay rights, like it or not the nation is polarized, as is the globe. As much as one side or the other might want to think they have a clear advantage over the other all the time when it comes to numbers, that just isn't true. As a result stunts like this do nothing but make the problem worse by basically throwing oil onto a fire.
For gay rights victories in comics, people should be looking at this PR stunt a lot less, and more towards Stormwatch characters like "Apollo and The Midnighter" and similar things. It's not like there aren't any gay men as super heroes out there in the major universes, it's just that they represent a minority prescence to begin with, and this kind of intergration is a slow process. If anything the whole "Green Lantern" stunt has probably done more damage than it has good for anyone who supports that cause.
As far as comments on the representation of the "ideal family" well again, that's what things are like, and have been like for the majority of people. Up until recently the US was strongly dominated by whites in terms of sheer numbers, in recent years this has been less the case and we're seeing a situation where Latinos are going to replace whites as the numerically dominant faction in the US within a few years apparently. In general a minority realizing he is a minority is not a huge thing, and any complex he develops based on that is his own problem. It's sort of like a white guy living in Japan or another nation, and pretty much holding to say American principles, he might be tolerated but is hardly the majority or what people are going to be going out of their way to cater to. As they say "when in Rome, do as the Romans do", as a minority it's your job to try and fit in, not force the majority to conform to you.