Doesn't seem like you read the article I linked then. So I'll post an excerpt.
How is it (Casual racism) different from other types of racism?
Some associate racism with a belief in racial superiority or deliberate acts of discrimination. Casual racism concerns not so much a belief in the superiority of races but negative prejudice or stereotypes concerning race.
Unlike overt and intentional acts of racism, casual racism isn’t often intended to cause offence or harm.
Doesn’t the lack of intent mean that casual racism isn't really racism?
One of the obstacles to having an open conversation about race is the tendency to downplay things as not “truly” or “really” racist. This can embolden or encourage prejudice.
You don’t need to subscribe to doctrines of racial superiority or incite racial violence to say or do something with racist implications.
Racism is as much about impact as it is about intention. We shouldn’t forget about those who are on the receiving end of discrimination.
If people have such care and concern over someone being labeled a racist, given his actions i'm proposing a concession.
Maybe just call him a "casual racist" or a "Part-time racist", "Seasonal worker for the department of racism" maybe a "Dabbler in the arts of racism" is more poetic.
No wait, "Lieutenant Govenor in Charge of Racially Insensitive tweets".... probably too lengthy to fit on a plaque.