It's ok to read someone else's research. But if you automatically dismiss anything that disagrees with a previously held belief, you aren't researching, you're looking for confirmation. You can find confirmation for just about anything.

It's one thing to be critical and say "maybe the specific scenario presented here doesn't really apply to me." It's quite another to say "this can't be true because I read something before that said the opposite."

Most people "doing their own research" fall in to the latter category.

You should listen to your dip shit uncle who says "mainstream media is lying to you, also listen to this flat earth dude"

Perhaps, hold an opinion and then go on to Google to deny it... Sounds wrong....

No, that's about right. If you have an opinion, you should be challenging it with additional information. The key is not tossing anything anything that doesn't already agree with your opinion. Going in with the understanding that you are looking for information that proves you wrong is a good approach, though.