From later in the article:
Last year, a Catholic lawmaker from Spokane and his supporters stirred up a hornets' nest when they sang Christmas carols in front of the giant holiday tree that dominates the Capitol rotunda in Olympia. Rep. John Ahern, a Republican, said the Washington-grown fir is a holiday tree, not a Christmas tree.
What's up with that? Why would singing carols generate controversy?
What's worse, they probably sang "Walking in a Winter Wonderland", which somehow is called a "christmas song".....