If it's going to compile without any warnings I'd rather the app crash rather than continue execution with rogue values as it does now.
There is so much room for things like corrupted files or undocumented behavior until it crashes. Without the compiler babysitting you it's a lot easier to find broken variables when they don't point to garbage.
Still learning, they just covered compiler flags in cs. They didn't go into detail yet though.
Edit: I've used python for years and they have something equally dumb. You can have a function in a massive application that is broken and the moment it's called, the application crashes.
At any other point the application will just run as if nothing is wrong even though python evaluates everything at runtime. I'm sure they can't do much because the initial launch would be slow.
C does exactly what you tell it, no more. Why waste cycles setting a variable to a zero state when a correct program will set it to whatever initial state it expects? It is not user friendly, but it is performant.
Odds are that your computer doesn't export any language where it will do exactly as you say (amd64 machine code certainly won't execute exactly as written). And how much difference it makes varies from one language to another.
But the specific example from the OP, of uninitialized variables, is one of those cases where the C spec famously goes completely out of line and says your code can do whatever, run with a random value, fail, initialize it, format your hard drive, make a transaction on your bank account... whatever.
It wouldn't be that much processing compared to the rest of the app. It would lot more efficient than running an effectively infinite loop or arithmetic on an arbitrarily large number as a result of an unsigned variables.