ED can be caused by a mental block such as self-esteem, anxiety, depression, nervousness, overthinking or focusing too much on maintaining an erection, or other mental-health/health aspects. I think porn can be a negative to your sex life if it is the only thing that can get you hard, I know because I've been there and I had to cut it out my life completely and I have no regrets. There's like a dissonance thing between porn and sex for me, and I failed to separate the two during sex personally. My mental state doesn't always help, but I most definitely found it troubling when I'd be butt naked in front of a gorgeous girl and couldn't stay hard for shit no matter how hard she and I tried.
I basically had to rewire myself mentally, and find a way to no only get a hard on from visual and audio ques, but find other things that turned me on. I mean, I'm a lot better now. But I'm kind of glad I don't really have to rely on the temporary high of porn to get a quick nut anymore. I only masturbate when the urge actually comes up instead of out boredom. Now I am not part of nofap or kill pornographers, just giving my personal experience. I don't really care to prove the scientific credibility of it... I mean, after all, people are still crazy misinformed about the science of sex. So it's a good thing we have this thread to help some.