Anybody who keeps removing categories from articles for no reason at all will be facing a short ban. Consistently do it and the ban will be longer.
Aiden1700 or whatever his name is has been consistently done this for every article he edits, he removes all of the categories. I have tried to explain it to him and he continued to do so and is now banned. He is the only culprit if I'm honest that does it but I felt an announcement should be made as I've had to go through all the pages and re add all the categories. Unnecessary work for me. That's all really but all the main contributors are doing good work on the site so keep it up.