Corneliab, there are plenty of ways to convey your feelings about someone's work without grinding them into the ground. Even if you do not care for their writing style or composition, I am almost certain you could be a bit less caustic in your opinions regarding the subject matter.
I am not saying you should not have your own independent thoughts when it comes to critiquing other peoples' work. I am merely stating that you can give them your ideas and, perhaps, some useful feedback sans the attitude and drama. I hope you can take this "weekend off" that I am bestowing upon you to think about what I have said and hopefully make some adjustments to your posting style accordingly. Thanks, and have a wonderful day.