What is so bad about people trying to do the right thing?

I was with a group of friends and they were discussing global warming. One of them got really upset and started calling people environmental wackos and saying it isn’t real. My response is ” wether you believe global warming is real or not, what’s wrong with helping the planet?”. To me, it was more about his ego than being active and actually doing something good because he likes to hear himself talk. I’ve met quite a few people like that.