The current issue aside, racists and xenophobes basically always attempt to evade responsibility by claiming they were "only joking". Such claims should be tossed in the trash bin where they belong. First, it's not a joke, and it's not funny. Second, they're lying...they didn't intend it as a "joke" and don't really even understand what a "joke" actually is, for the most part. And third, it's not relevant whether it was a joke or not.