But what does it mean 🤔🤔

yeah. you need lots of code to make dangerous code. single lines could never be a problem. we all know this...

the worst that I can think of is DUP CAT DUP CAT DUP CAT DUP CAT DUP CAT, blowing up the stack size exponentially

the solution is to put a limit on stack element sizes and the stack itself, as this is also possible via other means but somewhat more expensive