There's 830 open and confirmed wrong-code bugs in GCC at the time of writing. Compiler bugs aren't as rare as people think: https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=NEW&bug_...

I think it's just common for people to assume they're wrong and change things blindly rather than carefully checking the standard for their language (assuming their language even has a standard to check). It doesn't help that before AddressSanitizer and co. existed compilers would just do all sorts of nonsense when they detected possibly undefined code in C and C++.