I am aware that the phrase "climate change deniers" is in wide use. That does not mean it is not insulting. As I think I've said elsewhere, I have yet to meet anyone who denies that climate change happens. The debate (when one side stops calling the other side names) is about what causes climate change. On the one hand there are people who think the planet is doomed by human activity and on the other there are people who are studying the effects of all kind of things (as yet poorly understood) that affect global climate and who say, just a minute, what about this, and this, and this, and this....?
I personally am not insulted by any names people wish to call me, but I know some people are insulted by the implications in the phrase "climate denier." The fact that mainstream journalists use the phrase does not make it OK, just as the fact that "nigger" was at one time in mainstream use did not make that OK either.