I will not pretend that I have much knowledge of Sikhi.
The Guru has taught me that everyone is equal. Everyone has the same blood running through their veins. Every one has the same spark of Lord within them. The only division in this world that I recognise is that between the Gurmukh and the Manmukh.
The Gurmukh follows the Word of the Lord. He is free from the five demons, including lust. There is only one true form of Love, and that is Love for the Lord. All else is lust.
Men may "love" women. Men may "love" men. Either way, it isn't real love, it is simply lust.
Homosexuality used to be frowned upon, but is gradually becoming accepted. Leonardo da Vinci was said to be homosexual AND kept a 10 year old boy as his "sex slave". That is now called paedophilia. It wasn't frowned upon in the past, but it is now. In America, in some states, people commit Beastiality (and it's not always a man penetrating an animal; the reverse has happened, and women also commit such acts) AND it is accepted (ie it is not illegal).
These laws/rules are made by society and not the Lord. Man makes his own laws and suits them to himself. It is man who calls himself homo or heterosexual.
IMO, although homosexuality has been around from the beginning of time (including in animals), doesn't make it right. Evil has been around - people committed murders, rapes, and other crimes - since the beginning of time. Still doesn't make it right.
I believe that if we follow the path of the Lord, we will find the True way to live. I believe that lusting after another (male or female) will lead us to the wrong path. I believe we should be "asexual" in our thoughts - ie not to lust after anyone, and that marriage and children are there for procreation - to produce physical bodies in which other souls can enter whilst in the cycle of birth and death.