Comment by imtringued

You're merely attacking his particular suggestion and using this as an argument to defend UB, when those are completely independent concerns.

What people want is for a compiler that assumes that all pointers are aligned to use an aligned store or load instruction whenever the compiler wants to issue such an instruction. There is no need for UB here.

In other words, they want the compiler to stick with the decision it made and not randomly say "I can't do the thing I've been doing correctly for decades, because that's UB, my hands are tied, I must ruin the code, there's no other way."