Any issue important to more than a few dozen people will involve propaganda, falsehoods, and exaggerations from both sides of the issue. Simple fact of statistics and human nature.
Letting that affect your evaluation of the facts is a mistake.
I never said I will change my opinion about the issue because of that. Only that I am disgusted by this behavior.
As a more practical effect, just a tiny speck of falsehood in the discourse of "my" side, turns any attempt to convince anybody on the "other" side as an endless discussion about that silly speck, agreeing that it is false, but nonetheless the main cause remains true. It is very tiring. Exaggerated propaganda is useful to create stronger echo-chambers, but not to convince people who are outside.
I find this behavior deeply hypocritical and irresponsible. Worse, it is unproductive, because even a minimal sensationalization may trigger a lot of misguided (but sincere) opposition from climate deniers. Heck, even many rational people may be alienated by this!
As a matter of principle, I am disgusted by propaganda that contains falsehoods or exaggerations, even when it is for a good cause.