Well, there's a couple of things wrong with your comment.

Saying a white person with a swastika is a trashy racist is in itself a racist comment since you do not know for certain the circumstances. The Nazis used only one type of swastika, and certainly if the white person in question had that swastika they would be a Nazi (or a very unfortunate Buddhist), if they had any other swastika they would be a Buddhist or a Hinduist.

Second saying a swastika is a religious symbol only in an Asian country with a heavy Buddhist population is infringing on the freedoms of that religion. Buddhism is one of the fastest growing religions in the Western world and both Hinduism and Janism also use the swastika, if a white person joins those religions they aren't allowed to use the symbol?

Your argument basically equates to the Christians and the KKK. Since the KKK used the cross as their symbol the Christians shouldn't use it any more. Buddhists and Hindus continuing to use their swastika is empowering, every one, white or otherwise, that uses it takes power away from the Nazis.