In society's treatment of homosexuals, we should
a) "allow" them to have all the rights enjoyed by heteros, and live as "normal" people.

We have already achieved this.
They have the same right to marry someone of the opposite sex, and the right to enter in to a civil partnership with someone of the same sex.

Like everyone else they do not have the right to marry an underage person, a close relative or anyone of the same sex.

All those three limitations should be subject to scrutiny and change, but there will be people who will have valid objections to any change.