I think (and this is just my opinion) he mentions it because it's (sadly) another card it (KP) can play, the race card. By mentioning it first, he's taking out her ammunition so to to speak " you're picking on him not just because he’s disabled, but he's disabled AND black"
This is just an opinion, as I have done extended work in media PR my guess is that Alex is saying it first so it (KP) cannot raise the agenda.
Don't forget, we are living in an age where every denomination, creed, colour, ability, disability, gender and sexuality is nit picked to the max. He's covering his bases and from listening to him back when, I don't think he's a racist, I really don't.