Things are just balancing out. When homosexuality was illegal, anonymous casual sex was practically required so a man wouldn't be found out or be blackmailed. When homosexual acts between consenting adults were decriminalised there was a sense of freedom and a chance to differentiate a gay identity separately from a straight one (which was "the norm" of marriage, kids, monogamy etc)
Now we are moving on past that, marriage is legal in many parts of the civilised world and people have more CHOICE to do what they want to do with their private lives without feeling pressured in to fitting in, whether that's pressure to conform to monogamy or playing the field.
Monogamy is NOT trying to ape a straight lifestyle as many gay men have tried to call it in the past, some people of all persuasions want to develop a deep relationship with one other person, this isn't something exclusive to straight people, just like only wanting no strings random sex is not exclusively a gay thing either.
Choice is always a good thing.