It's a good cause, and I don't want for a moment to convince people not to give, but I do want there to be a discussion about this. Why is it necessary to have a conspicuously Jewish group that gives to causes other than Jewish ones? I think there are some good reasons. For instance, a lot of Jewish activists work with Churches because there aren't enough Jews in an area to recreate the organizational structure of the Church groups. If this gives Jews a way to act in ways they already want to while doing it within a Jewish space where they're more comfortable and respected, then that's great. But a lot of it feels to me, for whatever my feelings are worth, like they're acting specifically against the stereotype that Jews only give to Jews.
To that, I think the most appropriate response is to point out that Jews, in fact, give time and money to all sorts of worthy causes. If people don't notice, because people never really notice Jews,* that's their fault. Would you be shocked to hear that there are Jews who give to Greenpeace, the ACLU, or the NAACP? Well, a lot of people would for some reason. Furthermore, we really ought to ask: is there something wrong with giving to Jewish organizations? Certainly Christians give to Christian organizations all the time. Are Blacks who give to organizations like the NAACP seen as selfish? Are Muslims who give to CAIR seen as selfish?
When the motivation is to defy the stereotype, as opposed to pointing out the inherent stupidity in the stereotype, I don't think that ever really works. In fact, I think it gives the stereotype a certain strength because it reifies a standard of behavior against which people can be judged.
*Seriously, a friend watched Apatow's Funny People. I asked her about the Jewish content, and she said she didn't notice. There was a bit in the trailer about Seth Rogen being Jewish. Adam Sandler accuses him of hiding it, to which Rogen responds, "my face is circumcized." Flew right past my friend.
In that vein, I think the Andy Samberg bit, "People often come up to me and they'll say, 'Hey Samberg, I didn't even know you were Jewish,'" could be interesting, but it goes in a different direction.