By this logic Cullen is also racist for being gated to elves and humans only. Why won't he love my dwarf? She loves him! :/ I won't deny Solas is racist, but not because the romance is race gated.
Honestly, sounds to me like you need to let your elf dump Solas and go after Cullen.
Yeah, I wouldn't put any stock in the race-gated romances meaning they're racist, since the only reason they're race-gated is because they were added late and the devs couldn't do more animations for more races.
And you know, if your character is really super serious about the whole breeding with humans thing, you could make her be "forever alone" and deny her the Cullen romance. She won't be popping out more elves that way, but neither will she be having elf-blooded humans. In that case, it depends on what kind of sacrifice she is willing to make along those lines. I think you could have a really glorious, and super angsty, headcanon revolving around this.
Sounds like my canon Inquisitor
Alas, poor Meredith. Poor glorious, super angsty, forever alone Meredith

Funny that in an earlier conversation he says there's nothing worse than betrayal.
Could never make a Solasmancer.
This isn't quite true, he says:
"An enemy can attack, but only an ally can betray you. Betrayal is always worse."
He doesn't say betrayal is the worst thing in the world. But to be honest, the more I think about it, the more I realize that he doesn't really betray us. Or at least, he tries to do so as little as possible, because he knows it's a terrible thing to do and go through.
This is why despite it being a fairly dumb thing to do, he saves your life in Trespasser, even if he hates your guts. This is why he explains his intentions. Instead of just letting you die or putting you out of your misery, he saves you. Because if he didn't, it would be a betrayal. Instead of saving you but not telling you his plans, he tells you, because that way you can't be betrayed, not really. Because before you actually start fighting each other, you know where you both stand. He doesn't take you by surprise, he lets you prepare, thus minimizing the "betrayal" as much as possible.
It's to the point where it's Honour Before Reason. To me, that helps me realize why he lets you live and tells you his plans, and makes him a bit more sympathetic, too.