I assume the undesirables are gay guys? I don't recall at any point during my Masonic journey, from the petition to being raised, being asked if I currently was or ever had been a gay man. I don't know the qualifications your talking about either. If it's a matter of "living in sin" then anyone that smokes, dips, drinks, over-eats, looks at porn, looks at other women sexually at all, divorced and any other endless sort of sins one can commit, would be considered "living in sin". Masonic law is not just Christian law or Islamic law or whatever, it's all religions in Masonry. All of them... It's subjective from person to person. Not every gay guy is walking around with flowers in their hair or cross dressing either. Some you may never know it. If you want to black ball someone, however, because you assume they are gay, you have that right. But just consider not judging someone because they are different than you.
As for social change, black men weren't always allowed in lodges. Allowing them has turned out completely fine. Eventually, gay men will be joining as well. Btw, I don't think 90% of lodges have a bunch of young, effeminate gay men beating down the doors to join and hang out with some middle to older age guys. Just saying, it's really not a big problem I don't imagine and like I said, you can always blackball someone if you want to do so if you don't feel they'd be a good addition to your lodge.
The only reason I'm saying this is because we are supposed to be open minded to others and not judging them in any way. If someone is hurting others? I say they don't get to join. If they own some business that rips people off or they are just joining to get business connections, then they don't deserve to get in. If they were gay and not in it for the right reasons, they don't get in I say. But if they are growing spiritually and philosophically, I don't see a problem. If someone is minding their own business and not bothering others, I don't have a problem with others lifestyles.
Respectfully