C did do ‘whatever this CPU does’, and then the ANSI C committee broke that (probably by accident). That's what the headline post is about: “Those origins of C were there first”.
The ANSI C committee certainly did not break this. UB always meant that ANSI C simply did not define what happens in this specific case. This could mean "whatever the CPU does" or "whatever the compiler decides". What caused problems then was that compilers started to aggressively exploit UB for optimization (and customers probably asked for such optimizations) treating programs with UB as invalid. When this went to far and caused problems, compiler vendors then blamed the user and the standard. But obviously it is completely at the compiler developer's discretion what the compiler does, so customers should just push back and request changes.
In the vast majority of cases I'm glad that my programs run fast. sure I have to do some work to avoid undefined behavior, but most code is correctly defined, and the exceptions are bad code that I need to fix anyway as even if the behavior was 100% defined to C it would still be buggy as in not do what my users want.
