Who owns the building? That is who gets to decide what the room is used for. Unless you're a Christiano-fascist?
My my, you have a profound sense of history. The CHAPEL was first opened in 1603, IIRC, because the Christian faith was integral to education at the College at that time. IT served as a chapel well into the 70's I know cuz I was there and attended CHRISTIAN services there. The building can remain authentically historic as a Christian chapel without offending people of other faiths who choose to meet and pray there.
Don't you get it? If YOU can't pray because the icons of another faith are in sight, then YOU have the problem.
The College has MANY options to place a non-denominational chapel besides the historically significant Christain chapel in the Wren building. The Student Union is about 150 yds away and has plenty of available rooms. The College is making the willful choice to remove the cross when other options are more suitable to the history and legacy and sensibility of the community.