As part of my job as a photography instructor, I participate in critiques on a regular basis. I've learned to temper my critiques so that they are critiques and not opinions, because I'm providing feedback to students. Those students are coming from all different backgrounds and approaches to photography. Everyone has opinions, and they're certainly valid, but unless the opinion is explicitly requested, it's best to focus on four things when providing critique: what was the photographer's objective for the image, what about the image works to support that objective, what doesn't work, and how they can improve the image. I don't think it serves the hobby to discourage people, because their goals and aspirations are different from yours/mine. IT can be hard to do, when someone presents images that they're proud of but violate every principle of aesthetics (and even sometimes ethics) that you hold dear.