Yes it would as you know.
I can show you thousands of posts and reams of media attention which seem to indicate that the "Holiday Trees" do in fact have a religious component. Despite what Sea-Tac says. You and Sea-Tac contend that in this circumstance they're not at all religious. Perhaps a court would agree with you, but I doubt it. That said, it's a silly controversy. Holiday Trees are Christmas Trees, and Christmas Trees have a religious connotation to most people. They see them and think of Christmas. Which is a religious holiday.
Can you point me to several cases where "Holiday Trees" were displayed, other religous symbols, were specifically barred, and the courts said "fine"?
Christmas Trees are associated with Christmas, what's wrong with recognizing that?