I can't say about any other questions that got removed, but I would guess that the question "What Do These Groups of People Have In Common?" might have been removed because it doesn't sound like a question an individual would honestly ask another or would want a singular answer for . . . if that makes any sense at all. Naturally, many questions yield different opinions that can lead to a discussion but, that question sounds a little more like something a teacher would ask their students, specifically, as a class discussion starter (or as a question they already know the answer to) rather than a question one would ask a singular person. It's more of a question you would open a forum discussion with, rather than asking say, "What's the difference between a Protestant and a Catholic?" or something like that, which could lead to a discussion but, can, also, be easily answered by one person. I can't say if a lot of your questions were taken down for similar reasons but, I think a good rule of thumb in Questions is asking yourself if you would ask this question to a singular person (or would be happy even if just one person answered it). Maybe all it would take is just rephrasing the question. I think they just want people to ask questions they honestly want an answer to rather than asking something with the intention of starting a discussion (whether or not one happens anyway). I, also, think they like questions that one person could easily answer or make a hub out of. I don't know, I may be completely wrong but, that's my impression anyway. Sorry you've had such trouble and, hopefully, this answer helps you out a teeny tiny bit . . . But, if you still think you've been targeted unfairly, I agree with dashingscorpio and just contact the Hubpages team and see if you can get a explanation from them directly.