Here is the problem I have with celebrities and their views:
They often get access to a speaking forum that most regular folk will never get due to their celebrity status. Many of them and the media (in general) treat them and their views like they have some magical insight to politics, religion, whatever.
Because they get an opportunity to speak out and share their views that most of us do not, they have a moral obligation, imho, to either NOT spout an uninformed viewpoint, or to inform themselves thoroughly on the subject, whatever it may be.
It is responsible to say "I am not informed on blah blah blah topic, so I will not comment". It is irresponsible to say "We need to ban those things" without doing any research on the topic. This is magnified many times over when this is done to a larger audience.
If any one person is conversing in a small group, spout whatever you want. When you have an opportunity to influence many (thousands?) of people with your view - be responsible and educate yourself first.
Rights come with responsibilities. With the 2A, the responsibility is somewhat obvious (at least to me and some others) - handle them with care. With the 1A, it is not as obvious, but one should exercise responsible behavior as well.
Applicable quote from Brad Pitt (of all people!)
"Reporters are always asking me what I feel China should do about Tibet. Who cares what I think China should do? I'm a ????ing actor. I'm here for entertainment, basically, when you whittle everything away. I'm a grown man who puts on makeup."