Oxford University consists of a number of colleges. It was the Middle Common Room of Magdalen College which voted to remove the portrait of the Queen. The total number of students at all the Oxford colleges is 24,000. There are 403 undergraduates at Magdalen, and 173 graduates.
I don't know whether the middle Common Room admits mere undergraduates, or if it is just open to postgraduates, but the number of people actually entitled to cast votes is either 403, 173 or 576. We don't know how many cast their votes, or how many were for and how many against.
So out of 24,000 students at many colleges, a maximum of 576 (or maybe 173) students at one of the Common Rooms in one of those colleges decided by a majority vote to remove a portrait which they were not being forced to display, and it was probably only 173 of those 576.
The end of the world is not nigh.