if you really wanted to fix this you'd have to apply textures to the back side of geometry, which is generally a complete waste of time because nobody should ever be seeing the back side of a wall anyways
you're asking them to make an invisible wall to stop you from wallclinging near ceilings which would not only nerf a very popular strat (jumping to cat) but also cause immense issues for anyone actually trying to play in that general area (read: mandos colliding with the wall, losing all velocity, and then getting shot to death)
Imagine how many maps and angles you would have to "fix" and how much work that would take also why would anyone take MB2 that serious.
I mean from my standpoint I pretty much play this to have a giggle not to stomp people since taking something like this so serious isn't good.
There's not much that can be done about this beyond improving camera pathing code. It is also very likely that area portal culling might hide any players in the room visible like this so it is not 100% reliable.
Also worth noting there are much better and more useful ways of wallhacking for Jedi/Sith. Use the Force, dude!
Watch the "Exclusive Footage": Timewasting Places. You can do that on many maps where this bug works. On Kamino you can do it here (though there may be other places too):