There is plenty of excuse for it! You want to speak to me about lack of trust amongst men? It was your kind who didn't trust us. We didn't always have the Statute of Secrecy, you know, it's only been around for a few centuries. There was a time we were able to coexist, but then wizards and witches began to be persecuted all across the continent to the point that we were forced into hiding. The Ministry even went to your bloody King and Queen of the time seeking aid, but they were denied.

It's not the fault of Wizarding kind that things are kept separate now.