I like his vulgar style, but that's pretty much irrelevant here. How can one think debugger is a bad thing? I feel kinda incompetent as I am missing something

I like his vulgar style, but that's pretty much irrelevant here. How can one think debugger is a bad thing? I feel kinda incompetent as I am missing something here, does the inclusion of a debugger, even when not in use hamper performance or anything in particular in anyway? Is it the same type of debugger, where one could step through code and inspect objects or is this something completely different when it's related to the kernel?