I agree with everything you said. I don't have a problem PERSONALLY with what he did. I mean it's not my thing, but if he's fine with it and he's fine with the consequences of it, then go for it.  It'd be foolish for him to think there won't be consequences. 

It boils down to whether he A. realizes there will be consequences, and B. if he's willing to deal with them.  

If the answers to both of those are yes, then there shouldn't be a problem.

I think the difference in Lambert's situation and Bowie/Farrell/etc is that they didn't (at least I don't believe they did but I could be wrong) start out as a hearthrob of millions of teenage girls in the vein of an American Idol type situation.   

As for George Michael, my favorite album of his is (I believe) the first one that was released after he came out, and that's "Listen Without Prejudice Volume 1".   

And yes he was a heartthrob for teen girls who imagined he was straight.

What happened to him afterwards though?   His first album was platinum several times over.  Everything after that essentially tanked, whether they were good or not.

So this won't be all flowers and bubblegum for him, but hopefully people are more tolerant and are able to get past prejudices.