I wonder if there is a way to hide that icon:
Assuming you mean that entry as a whole and not just the icon:
Nope, currently not possible.
I'm pretty sure there are outstanding wishlist requests to have 'all..' at the bottom of listings instead of at the top.
So you could try to find those and support them, or make a request to never show 'all'.
(which I am guessing would have little chances of success)