I think the reason they are asking for money is because they don't have the facilities or manpower to deal with managing and distributing the "stuff" that people want to donate.
And let's face it, a lot of people donate junk.
I am NOT saying your stuff is junk, I'm sure it's not!
But can you see how in an imminent emergency such as this, where people have lost their homes and/or everything they own, the most pressing priority is to get them housing, medical attention and food, all of which cost money?
If you really want to donate your clothes directly to the victims, perhaps you can offer it up on craigslist, or freecycle. Or even better, take it to LOCAL organizations that distribute food and/or clothing directly to the poor.