I do not think there should be 'defunding'. I am not surprised by the knee-jerk reaction regarding it though.
I can understand why NPR, as an organization, was embarrassed by the statement of one of it's employees, but the termination I think was uncalled for. Any one statement can be taken out of context and well let's face it, turned upside-down and used against you. If people want to be offended, they will find a way to do so.
I do not think Juan Williams is a racist man, nor do I think that he was saying what he said to cause hatred towards a particular group of people.
When we start to filter everything we say so as to not offend someone, something, or another we lose a very basic right we have. We will sound like politicians that use a lot of words and say absolutely nothing.

Oops, I may have offended a group of people there.
I don't expect to change people's mind about this, but I did want to add my thoughts.
Regarding the people which he was talking about. I will say, oh do I dare? Yes, That of the latest attempts against the USA in terms of terrorism, all of them have been affiliated with that particular group. Are all members of that group terrorists? No!, but, all the terrorists were from that group. I am frightened when I see people that are clearly identified with that group. Why shouldn't I be? Are we not on the lookout for terrorist cells? We had one happen a few months ago, not too far from my home, and yes it was from that group. At the same time, I am afraid when I happen to be in a city environment at night walking down unfamiliar streets and I see a group of young men hanging around. I don't care what color/ethnic group/religion or other variable you can think of.
Should I not be able to say that I have fear and hesitation regarding this? As of this date, I have yet to hear that the heads of these groups/congregations that they condemn what is being done and remove themselves completely from the fanatics. Until that happens, I will assume, as most of us do, that they are in agreement with it.