"The Catholic Church, in general, has been slow to combat racism." 
This may indeed be the case in US. When we were in South Africa in the late 70s-early 80s, when apartheid was fully functioning, the Catholic and Anglican bishops (and most of the clergy) spoke out strongly against the racism intrinsic to the apartheid lawsto the extent that the government warned the people "Romse gewaar, Engels gewaar!" (Beware of the Romans, beware of the English!). They had a real problem when the Reformed Church in Holland declared the teaching (and practice) of apartheid a heresy. None-the-less, everyone knew where ordinary folk, black and white, could get actual support in their stand against racism. The Catholic bishops were equally strong when they stood against the systemic and institutional injustices of dictatorship in Malawi in the 80s (not racism but none-the-less good leadership against injustice and corruption). 

The Bishops do quite often do the right thing, and speak out against evil.