Activists have demanded that Muslims be kept at a distance and not be permitted close proximity to Jewish visitors on the Temple Mount.
The attack a year and a half ago the day after Pessach is one reason as the subsequent weak police reaction.
Here is another this morning I caught from this clip:
That is either a shoe or another projectile.
And another view of the results.
In this clip at the beginning, you can observe how the blue-shirted Mulsim, with his hands conveniently behind his back, runs interference and tries to body-block the Border Policeman: