Why is there so much disparagement of patients who try to bring up what they research to their doctors?

Disparagement?: I'm not sure who you're referring to about being disparaging. If you tell a doctor "i read this on the internet" they are likely to be skeptical without more information about the credentials of the source of the information. There is a wide range of stuff out there, ranging from dangerous to rip-off to outdated to accurate & helpful. Sometimes it's hard for people to tell the difference.