I'm sorry but my statement was not clear. I was not referring to people who give advice on your pictures. Of course, everyone has a right to his own aesthetic feelings. I'm a pretty good judge of what meals I eat and how well they taste although I'm not much of a chef.
On the other hand, once I start telling you how to prepare a superb meal, you'd want to know my experience.
Likewise, there are loads of people giving technical photo advice here. How do you sort through all that advice to see if it might work for you if you cannot see samples of their work and how they applied it? It's a way of checking references. Even if the advice is"valid", it might not be the result you want. Being able to see the advisor's samples, allows you to judge whether it's something you want to spend your time trying to do.