Because rightists care so much about gays. Balance in nature - ever heard of it, Pimpek? hahaha
Certain parts of society focus on different things, a soldier/officer will focus on discipline and strength as a preferred measure (as they excel in it compared to other parts of society while rivalling sport athletes in this regard), then naturally those parts of society that don't want order, discipline and strength but, prefers sensitivity, chaos or openness and voulnrebality will be opposed to such people.
So when a group of people (gays) who does not wish or gain pleasure from heterosexual relationships (from natural reasons to them) then they will be opposed to normal and natural order that supports heterosexual relationships in society (family, self-control or wish to not fall to bodily temptations)
Rightists are useally family oriented, orderly and wish for self control not only for themselves but, society as a whole as the benefits outweighs the costs. Leftists disagree on this since being fluid, adaptable and oriented towards others is more important and how one feels while neglecting intellect