From my brief look around the internet, there are two major comments that drew ire from commentators:
"Multiculturalism hasn't and doesn't help, because rightly or wrongly it polarises people so much."
the fact that he said the "n" word ("nigga").
The thing is, if you actually read the article more deeply, and recognised the prejudices and misinterpretation on the part of the 'journalist', the context suggests that Freeman is far from racist - rather, he understands how social structures and pressures shape the way people think. The multiculturalism thing I completely understand. The "multiculturalism" that Freeman is talking about is the political term, which has been about trying to get everyone to fit in, to reduce people to being as similar as possible. I agree with Freeman here actually - it's good to celebrate differences. Allowing people to be different, and celebrating that, might actually help us become more accepting of each other. (And it works both ways between any culture/race.)
As for the "nigga" one, he was talking about how rap artistes have started throwing it into songs, apparently just to appear cool. If that is true (about the rap artistes, I mean), then again, I completely agree with that.
But - and please excuse me for being lazy (busy, rather) - I found someone else who said this all and more, and far more eloquently than I probably could have.
edit (a few hours later): I've just seen some of the comments about Lucy Liu too, and...he's not racist, he's just very British. I'm not saying that all British people have such a dry sense of humour because I doubt that's possible (although the Brits - and at least one American - that I have found the most hilarious in my life do), but you really do have to know and understand British humour to not feel offended by him. So it doesn't surprise me that quite a few people have found him offensive... That said, this doesn't change the fact that he's not what most of them are accusing him of being.