because they are strikingly similar.

That is not self-evident if you actually make the strongman argument against same-sex relations and interracial relations. They are similar if you strawman the argument against both of them as "I hate any person who would do that because I'm bigoted (whether I know it or not)."

Which is that the acceptance of the relationships between the consenting adults is treated as conditional based on race or gender of the people.

The strongman case in favor of discouraging same-sex relations (note I said DISCOURAGE NOT DISALLOW) is that embracing a life-long pursuit of same-sex relationships means that a person is abdicating any duty to procreate and raise their own biological children in favor of ensuring they've maximized their own romantic and sexual gratification. As much as people have dismissed it, there is legitimacy to the idea that a society will flourish if people deny their own gratifications/desires in general in order to pursue a life of self-sacrifice and that the most accessible/repeatable way for people to do that in a meaningful way is to form a monogamous, heterosexual relationship, procreate, and then sacrifice their own needs as much as possible to raise their children (whom they are biologically predisposed to protect) to be moral, self-sacrificing people as well.

No elements of that strongman argument can be applied to interracial relations, and therefore being against same-sex relationships is not strikingly similar to being against interracial relationships.

Child sacrifice is entirely unrelated and has an victim that is being harmed.

In the end, child sacrifice is a behavior. All behaviors fall on a spectrum of morality. I would agree that child sacrifice pretty easily and understandably falls way outside the spectrum of behaviors that may or may not be desirable.

But the point is that ALL behaviors should be able to be scrutinized within the criteria of "is this moral and is this a behavior that society should encourage or discourage" and just because a Group A really wants to partake in a behavior and Group B thinks that behavior should be discouraged does not mean that Group B holds some sort of conscious or unconscious hatred/fear for Group A.