But you really dont understand what racism is. I would sugest educating yourself on that matter.
I would point out that any national group can be termed a race (I checked a dictionary to be absolutely certain). In fact it is a common practice. You are being overtly technical about it.
It is not a differentiation. It is something you clearly dont understand. Making fun of Scots in this instance is not racist and not persecution and not genocide. It is simply that, making fun.
If you are both having fun, I will withdraw but from the looks of it, you were riling him up and about trade a volley of insults.