Is arrogance a crime when all you're really doing is expressing the truth?
Arrogance isn't a crime fullstop.
Some people don't like those that sing their own praises, or seem too full of themselves, and I think we can all see why that might be - whether we share the view or not. But that's the point here I feel - it's all a matter of opinion.
If I were Sagan, I'd want to be aware of how people might respond to me, how my attitudes and celebrations might p*ss people off, and maybe temper them a little because I don't like to wind people up needlessly. But it's a moot point since I'm not Sagan! And, more to the point, Sagan being Sagan probably wouldn't care what others think! So we're kind of back to square 1!
Love him or hate him, your call. It's all pretty immaterial really. Personally, he makes me smile. Oh, and he's a bloody strong bike rider. I think all can agree on that.