Or Pony is not ready for the world. I mean, they don't even have arithmetic operator precedences [1]. If you're doing things concurrently it must be something uber-important, like censoring cat pictures, but apparently not arithmetics.
In Lisp and Smalltalk it's obvious enough how composite expressions are evaluated, and they don't have the usual infix syntax to begin with. Pony does and the different precedences are just a bad surprise. As far as that's a design decision, I'd call it bad design.
If you're going to complain about that, you might as well mention that the run-time system puts the terminal into a weird, pseudo-raw state that makes stdin/stdout act kind of funny, if you're not expecting it.
[1] https://github.com/aksh98/Pony_Documentation#precedence