No, two acts with different primary defining aspects are two different types of acts.
By definition, people of opposite sexes cannot possibly perform homosexual acts on eachother.
To accept a statement that they are the the same or even equivalent is to implicitly accept that sexuality is not an intrinsic part of a sex act. I don't accept that.
So you're suggesting that there should be two different terms for anal sex? One indicating the participants are heterosexual, one indicating that they are homosexual?
I agree with you that heterosexuals do not perform "homosexual" sexual acts. They don't do homosexual anything... up to and including homosexual teeth brushing, homosexual feeding the dog, homosexual walks on the beach. Still, any of these acts remain exactly what they are, regardless of the sexual orientation of whoever is performing them.
"To accept a statement that they are the the same or even equivalent is to implicitly accept that sexuality is not an intrinsic part of a sex act. I don't accept that. "
You don't have to accept that these acts are roughly equivalent on a personal level, because for you they would not be. They wouldn't be for me either. But it doesn't take away from the fact that.. anal sex is anal sex. That's why there aren't separate definitions. (I've never written "anal" so much in my life.)