The opposite of being anti-competitive is not simply competing, it's competing fairly.
It is pretty clearly free riding to take the creative output of another company, repackage it for money and contribute little or nothing in return.
The world is poorer when this happens because free-riders can freely have business models that "kill the host", that is, don't capture enough value to keep people working on the underlying product.
Perhaps the answer is "well it shouldn't have been an open source product then?" and then we all miss out.
Meanwhile Amazon celebrates turning off all their Oracle databases. Great! And they make a lot of money off the back of Postgres too. But try asking them for the code that bundles Postgres into a reliable managed database offering. Of course they won't share it. That's their IP.