This is true for anyone who gives you feedback on your writing. If it doesn't seem right, then question it or disregard it. If the person giving you feedback tells you that there is only one way of doing something, then take two steps back. Because there is more than one way to write a story.
Regardless of the source, it is best to treat all feedback that you get on your writing as suggestions.
If you belong to a writing forum and someone starts spouting what seems to you like a lot of blahblah malarkey, then ignore it. Seriously, there are so many ways to approach writing a novel and actually writing that novel that you need to do what works best for you. However, listening to how others approach something, thinking about it, trying it, those are all valuable actions to take. But, accepting it just because So and So said S0 and they are an editor/agent/publisher, no. That goes for me, too. Don't accept everything I say as gospel.
Note, I am specifically talking about the writing process and everything you do before you query your novel to an agent or submit your story to a magazine publisher. The editing process for publication requires dialogue and conversation. If you ignore what your editor tells you, you're going to have difficulty selling anything to them again. ;)