I only concern myself, if somebody is clearly being racist.

That has to be proven about Motley Morris. Until then I hold my stance.

They (Motley Morris) were obviously booked by the school. Their (Motley Morris) website makes it very obvious that they black up, by the picture and the first sentence in the first paragraph.
http://www.motley-morris.co.uk/

What more do they need to do. The school cocked up and Morris teams may well suffer for their action.