Isn't it obvious that all the implementation dependent behaviour isn't standardised?!
What weird mental acrobatics. It being in the standard means it is standardized! Standard basically says: we did not define the effect of this operation, so don't do that unless you really know what you are doing.
Would be very nice if implementation-defined behavior was not needed in the standard, but it's still much better to have standardized implementation-defined behavior than the standard being completely silent about some corner cases. This makes C standard
good, compared to poorly standardized languages where you can't know what happens by reading the standard.
And then there's all the undefined behaviour
Exactly the same for UB! This is the strong point of C: UB being standardized, so just read and understand the standard, don't do UB, and you are good to go.
Having such standard is not obvious at all.
Surgeons have to be rigorously trained and pass exams, and are regularly monitored by formal regulatory bodies. Anybody can call themselves a programmer and practice [sic] it without being monitored.
But anyone can also buy surgical knives freely and do whatever with them. And doing something with C where human lives are at a stake, say design an autopilot for a passenger aircraft, also requires at least some form of monitoring by formal regulatory bodies. Anyone is free to use surgical knife to peel an apple, even if that poses a risk of cutting oneself. My surgeon analogue is thus valid.