Once again, even if I accepted that statement as fact, did you hear Tyson call anyone a denier?
Many, many times....
[ame=http://www.youtube.com/watch?v=FZYMD0oSQQQ]Neil deGrasse Tyson Explains Climate Change Deniers - YouTube[/ame]
In that clip I heard him use the word "deny" and I heard him use the word "denial". They were used appropriately in the context in which he spoke.
I did not hear him use the word "deniers", much less use it as a pejorative.
Feel free to type it into youtube and knock yourself out.