They are not complaining about the price, but about the closed source nature of the product.

I'm not running Traefik in production. The features that I need are all closed source so I moved on.

Sure, it's a choice but I think it's more that don't pretend you are open source when your carefully hide things behind closed sourced paid licenses. Be like Microsoft, we have eval version but if you want to use our Windows Server, you will be paying up. Cool, I can make a decision about your software with that in mind.

A choice is a far cry from the "standard" the title purports.