Akenaton,
This really sums it up well. You say:

"...no sensible person would seek to criticise anyone on grounds of their race.....but we should all be FREE to criticise others, and be criticised ourselves on our behaviour......how we treat our fellow humans, and what we practice..."

No one is being Orwellian here, and I don't see anyone trying to shut you up.

Your sentence addresses the very crux of the disagreement.

You think race is congenital and sexual orientation is a choice.
Many, many others think they are both congential.

Thus, we completely agree with your statement "...no sensible person would seek to criticise anyone on grounds of their race.....", but we add "or sexual orientation".