For the second time in three weeks, Bruins goaltender Tim Thomas embroiled himself - and his team - in political controversy, exercising his right to free speech, but refusing to practice it for reporters in the locker room. It left some to wonder if his penchant for exercising his First Amendment rights in the social network strata had indeed become a distraction. Thomas, who cited political reasons for his refusal to attend a White House reception held Jan. 23 by President Obama in recognition of the Bruins’ 2011 Stanley Cup championship, posted an expression of his beliefs on Facebook before the Bruins’ 6-0 shutout loss at Buffalo, saying ’’I Stand with the Catholics in the fight for Religious Freedom.’’