Well, that depends on the argument, but presumably if at some point you state "the moral thing to do is to reduce surplus so that other people may have increased surplus" and no one is really doing that, you have to question the moral argumentation somewhere.

For instance, were I to make that argument, and were you to ask me "During the pandemic, did you Doordash any food? How much did you tip? How much money do you have in your bank account?" and it turns out I tipped a very small fraction of the money in my bank account despite "the delivery driver risking his life to deliver nutrition you require to survive" then you might be well within your rights to ask me to justify this behaviour of mine contradictory to my stated morals and see if the argument extends.