Depends what the KKK app does. If the KKK app spouts nonsense about white supremacy and why they should not be minority-sympathizers, then yeah, I'd say to allow it, because it's their right as expressed by the society.
There are things out there that claim why men or women are inferior, and I think they have a right too exist too.
And I think anti-semantic taglines should be admissible as well.
Reparative therapy is a tool, and like any tool can be harmful or helpful. Reparative therapy techniques have been used in legitimate physiological therapy.
Visualization? Social Skills Training? Therapy? Interventions?
The big thing that comes to mind is all the effort dumped into the Autistic.
It's all a matter of perspective.
I have yet to see any credible research make a solid determination as to homosexuality being biological. The hormone difference is contradictory to itself. And there have been no evidence like evolution's evidence.
And in light of that, and even despite any future credible research, people should still have their right to their bigoted views. They should only be restricted on their actions that act upon others.
You have your right to say those things too, and I agree with your view that they are "sexist, egotistical, hypocritical bigots". But this isn't about the greater fight of LGT, this is about their right to an app.