Mass. may not be nearly as liberal as it is said to be, and there are some culturally conservative Dems, but it is still quite liberal by American standards. Even the most conservative counties in Mass. are still less culturally conservative than most of America. For example, the current MA-3 is relatively culturally conservative and still elects liberal Jim McGovern. Perhaps northern white working-class Catholics prioritize other things above social conservativism.
BTW, has anyone seen polls/results by county for gay marriage/marijuana in Mass.?
I get the impression of Mass. being pretty culturally conservative, still. It seems like despite their support for 'liberal' policies, they're still very "cut your hair, hippie."