Wow, those responses from 'Toast' are pretty awful, aren't they?
I can only hope it was supposed to mean 'We deal with one particular agency and only choose from what they offer us and they are the ones who can't provide a decent range of ethnicities with the qualities we are looking for." Rather than what sounds a lot like "Non white models don't have what we're looking for".
But, either way, they really need to sort themselves out - if they want to show a better range of models, I have no doubt they could find them, or encourage a model agency to find them. They just don't really want to.