You can make exactly the same case about tonal voice leading rules too. Rules are a "pointless conceit" by definition. "Free atonality" can, again by definition, do anything it wants, including emiting a J. S. Bach fugue or whatever. This is a tautological case.
In fact the whole point to music is rules. We have expectations about what we hear and how that works and what it means, and you write "new" music by breaking or bending just a few of them, or otherwise finding ways to do stuff other people haven't.
And Schoenberg was trying to find a way to write a new set of rules. It didn't catch on, for the most part, but it wasn't "pointless". You can hear tone rows and learn the rules and "understand" a 12-tone piece in ways that you can't for arbitrary noise. And that's kinda cool.