@HeartsDo: Thank you for the question, which is a good one because there's little policy basis for removing other users' rights (it's mostly by unwritten conventions, customs, and practices), so I'm happy to answer it. Basically, the answer is 
yes bureaucrats and, even really administrators, can remove user groups from other users where either (a) it's clearly a test that has been done or (b) it's a duplication of an existing user group. In practice, it's recommended that bureaucrats or, at least, experienced administrators do this. Now, I generally do like to wait a few weeks to a month or so before removing such user groups. In this case, though, I'm not sure why @Naleksuh: re-added the testgroup that the user apparently removed, which seems to be the case. While maybe not needed, it was a case of the user reverting all tests in good-faith, which I think we should encourage
