There are two possibilities here:
(a) You find the argument convincing, in which case you should put on your big boy pants and actually make the fucking argument
(b) You don't find the argument convincing, in which case you shouldn't waste everyone's time with it
If anyone would like to present a secret third thing, please do so.
(c) The argument, as presented, can be read more than one way, and by 'steelmanning' it you are choosing to read it charitably and respond to its strongest version.
I think that's basically what the other guy meant: we can read "the world should accept some bad things" to mean something like "fuck you, we'll do what we like and the world will suffer the consequences" (less charitable, arguably a strawman) or something like "there will not be literally zero costs, but we think the shared benefits will be much greater" (more charitable, arguably a steelman), and he was choosing the latter.