It depends, is that work based on the free work of others?

Taking advantage of the community and not contributing back for others to benefit (as you have, for free) seems selfish to me.

Maybe if he proportionately (based on LOC or something) donated any income to his upstream dependencies?

...but I suspect that wouldn’t leave much.

I saw it as him encouraging the community to join him, on behalf of all starving developers who are giving big businesses a free ride.

Other contributors were using a very permissive license, that allows sublicensing. They were okay with a proprietary software company embedding their code into a proprietary product and selling it, they should be okay with this as well.