When you (not the jungler) randomly start baron without your jungler there and the enemy jungler standing literally over the wall, it does not matter whether or not your jungler "should have been there." WHEN the baron gets stolen, it is YOUR fault. Why are you doing baron without your jungler there?
The fact that I have screeching auteesies crying and moaning at me as a jungle main for their fuck up is really what makes the game not fun to play.
Jungle already feels like shit to play. Shaco jungle especially so. I don't also need some screaming toddler flashing and healing on top of me in babyrage because they can't handle the fact that they're physically too stupid to understand why they're stuck.