I see this a lot on various forums I go on,mostly they are quite good,but occasionally I see some and they are rubbish,yet the only comments you see are how great they are,I don't answer as I never want to offend and I wonder if those answering are just complimenting for the same reason.
A lot of people don't want to criticize people's work for fear of looking like an ******.
As a photographer, and someone who work(s/ed) with pencil/conte/charcoal/ink and oil/acrylic/watercolour paints, when I post my work, I want genuine feedback. If it's good, I want to know what's good about it; if it's not great, I want to know what needs work.
I know that a lot of people who post their work aren't as interested in that honesty as I am... they're looking for praise for doing things.
It can be a bit of a mine field figuring out who wants praise and who wants a critique... if you offer a critique and it's received poorly, well, it gives you a pretty good measure of the quality of the person who takes offense.