You need a reasonable amount of evidence to prove almost anything is true.
No one, me least of all, is arguing against expressing an opinion on possible motive. Prejudice seems to be a very likely motive given what information we do have. You also can't rule out just plain mental disturbance yet either. Which is the rub. Reasonable assumption is not enough to condemn someone or demand others to do so.
Where I took issue with your comments uniquely is not so much the fact you were arguing with a hardline about your assumption(others have as well), it was the added caveat of claiming that taking such a hardline at this moment is necessary and wise. Which you seemed to be arguing in a few posts.