Frankly it doesn't matter whether you're black, brown, a woman, a man, use a wheelchair, use a walking stick, have a bald head, have one leg shorter than the other, have big boobs, have small boobs, have missing teeth, have a lazy eye, whatever, if you are offended by a ticking disability that the person can't control, and means no harm, then you just have to get a grip and accept that they deserve to be present in the world where everybody else is present, or remove yourself from the situation.
You can't control other people's actions, and with ticking disabilities, the person having the ticks also can't control them, but you can control your own actions and you can leave. Being black in this scenario isn't special, no matter how offensive you find it.
People with disabilities don't owe you their absence in favour of your comfort.