As such the stance is definitionally illogical which makes it flippant - it falls apart under even mild scrutiny.
I've seen about a billion variations on it now, it just gets boring to bat them off. e.g. "if the healthcare system is overwhelmed, you'll die in a minor car crash, so don't go outside, then you won't drive your car or stand near cars, then you can't die in a minor car crash anyway, err... but lockdown though!".
It's tautologically broken. The basic premise is of "not doing X, in order to not do X".
If we don't lock down and you break your leg, you may not get medical attention.
So let's lock down so that it's impossible to break your leg.
I'm totally happy to accept that contracting coronavirus could be triaged lower than acute chronic conditions, heart attacks, etc, that's an interesting debate to have because healthcare is scarce and therefore an ordering _must_ be chosen.
What makes no sense is just flinging our hands up and saying "well, stop the world for everyone instead".
Not everyone advocating lockdowns is necessarily so flippant about it. Some consider the costs carefully. Please keep in mind that hospitals were being overwhelmed long before vaccines were available.
(FWIW I'm not defending absolute lockdowns since going outside with moderate distancing appears to have been safe at every stage of this phenomenon.)