The maintainer literally responded to someone else making a similar claim in this HN thread to say that this is now the meaning of that license clause. Someone else posted the Cornell Law legal dictionary definition of 'commercial purposes'. It is really annoying that people who write software suddenly think they are legal experts who can make these kinds of ridiculous claims anytime 'licenses' come up. Instead of making stuff up off the top of your head as though it was factual, please defer to experts in the field. On legal issues this is particularly annoying.
> The term “used for commercial purposes” means the carriage of persons or property for any fare, fee, rate, charge or other consideration, or directly or indirectly in connection with any business, or other undertaking intended for profit.