Michael, you need to explain to your wife who seems to live in some kind of bubble, that as we go though life we meet thousands of people, most of whom we will never meet again. A surprising number of these people are incedibily ill - mannered, incredibly stupid or just plain arseholes. Keep that in mind and it's east to ignore them.
Go though life looking for racism everywhere and she will find plenty of it, but only in her own perception. A reasonable person will understand all that's happening is they are meeting their quota of stupid, ill mannered arseholes.