Quite a gesture.
https://www.theguardian.com/world/2017/mar/03/banksy-opens-bethlehem-barrier-wall-hotelRecent rumours point at Banksy's real identity being Robert Del Naja ('3D') of Bristol's Massive Attack - a group you should also look into, Bozz.
Out of all the Banksy theories, this one probably holds the most weight, for me. Again, there's quite a political impetus behind them, although it's not overtly obvious through their music. If you had the time and got a feel for what they're about, you could see why the link is plausible.
But back to the point. Good on him, them, whoever he is.
And by the way, if anyone's on Twitter following that 'real banksy' account, it's really not him..