This impressed me because Patrick Stewart is such a staunch LGBT ally and because defending civil liberties -- even of those you vehemently disagree with -- shouldn't be incompatible with being a good advocate.
He further explains this position on his Facebook page:
In my view, this particular matter was not about discrimination, but rather personal freedoms and what constitutes them, including the freedom to object. Both equality and freedom of speech are fundamental rights— and this case underscores how we need to ensure one isn’t compromised in the pursuit of the other. I know many disagree with my sentiments, including the courts. I respect and understand their position, especially in this important climate where the tides of prejudices and inequality are (thankfully) turning. What I cannot respect is that some have conflated my position on this single matter to assume I’m anti-equality or that I share the personal beliefs of the bakers. Nothing, absolutely nothing, could be further from the truth. I have long championed the rights of the LGBT community, because equality should not only be, as the people of Ireland powerfully showed the world, universally embraced, but treasured.