Parent probably implies "with the exception of unsafe" when he says "normal code". Unsafe code is supposed to lack many of the benefits of Rust's memory model.
It's incredibly useful to limit the regions of unsafety and use them to build reusable, well-tested safe abstractions, but it's a mistake to confuse that with eliminating unsafe entirely or ignore the possibility there could still be errors within them.
I'm willing to bet that the vast majority of Rust code (outside of std) is safe. I've written unsafe once ever, in years of writing rust.
I agree that it's unfair to generalize that debuggers have no use in rust, but it's fair to generalize and say that most rust developers do not experience segfaults, or other memory corruption issues that often call for a more advanced approach to debugging.
It's very much about project choice. I immediately ran into unsafe trying to test some functions marked extern. Then again writing toy VMs and GC algos.
You may not use the debugger often, but it's there if you need/want it, which is an important message that I think is lost with "all Rust programmers are print debuggers".
Congrats on only using unsafe once in years. That's pretty neat.