If I am honest, I'd have to try and understand the motive behind the comment / remark.
I firmly believe there's racism in all of us, but how we deal with it, and what are intent is, is hugely important.
Some comments are naturally insulting regardless of race, but when combined with a racial slur, they are provocative and full of malice.
Other racist comments can be as simple as a generalisation such as 'the Welsh are great singers'. There is no malice in that, but it's racist (not strictly a race, but in the wider context of xenophobia).
I think hand on heart, we all make value judgements on people. We see a skinhead with tattoos and we probably assume an aggressive personality. We see a frail old lady, and we assume a placid, well-mannered woman. In a similar way, if we want to paint a poster of England, we may well depict a man in a bowler hat, and if we want to depict a gang member from LA, chances we will create a black character. This is racism because we are making assumptions based on race.
In that sense, racism lurks in us all.
But this is a far cry from the vitriolic hatred of another race or culture. This is the person we tend to think of when we say 'RACIST!!!' - the nasty, vindictive insult hurling idiot.
So for me, I can find a case to want to educate some racists, and for others, I want to punish them. For me, there is a scale. That's not to say one form is less or more harmful than other, it is to say that the intent behind racism can vary massively, and it's important to assess that before we punish someone.