I'll be honest, if I see someone that is very large indeed, I do notice. Most people would. It doesn't mean I judge, or think horrible thoughts about that person - but I have eyes.
How does that work for somebody's skin colour, then? I too have eyes, and of course I notice if somebody is black, Asian, white, male, female, tall, short, clearly disabled, apparently able-bodied, whatever... but it's of no consequence to me.
I have older family members who would say "I met this black man at Asda today, who told me......" but it wouldn't occur to me for a moment to mention his race/colour, as it's irrelevant. I wouldn't pay it any mind at all; any more than if the person had been blond(e) or Welsh or used a walking stick; all that matters is what they said to you.
Whilst obviously acknowledging that surely some people with Tourette's can naturally be plain racist/unpleasant etc. - as they are people like everybody else, and some people are sadly like this - does Tourette's also subconsciously and involuntarily grab the mind of otherwise-pleasant sufferers to make their tics specific to the object of their outburst, as well as triggering the outburst itself?