The argument is: if you don’t have hygienic macros, a Lisp-2 is going to be less brittle than a Lisp-1.
The classic example is, imagine you have a function with a local variable called “list”, common enough. Now imagine you invoke a macro inside that function which generates a call to the built-in “list” function - also common enough. In a Lisp-1 without hygiene that breaks - your local definition shadowed the built-in; in a Lisp-2 or hygienic Lisp-1 you’re in the clear.
@nathan_compton, your sibling comment to what I'm writing now is [dead] (not [flagged]) but you're not shadowbanned, newer and older comments are still alive. I vouched for it but it's still [dead], you may want to reach out to the mods.
People should never use non-hygienic macro systems anyway, but even if they are using a non-hygienic macro, they should always use proper hygiene. Its kind of dumb to make the whole system weirder just to avoid issues which should never happen in the first place, in my opinion.