However you slice it, Hamas is a terrorist organization. Supporting Hamas is on par with supporting Breivik. Breivik was diagnosed with paranoid schizophrenia: Hamas has no such excuse.
CAIR (Council on American-Islamic Relations) has consistently funded and supported Hamas. Through its actions, it has supported terrorism. It is not an organization that ought to be permitted any legitimacy in our society. It claims to speak for all Muslims, but, when good, moderate Muslims denounce terrorism, CAIR attepts to intimidate them into silence. Perhaps as a result of its actions against moderate Muslims, perhaps because of its persistent ties to international terrorism, even the FBI and multiculturalism-friendly White House have cut all their ties with the increasingly disgraced CAIR.
It’s not like there is a dirth of respectable Islamic organizations one could support (some can be found in my links on the right sidebar): it’s just that CAIR is not one of these.