"Honestly I think the sense of entitlement nowadays is way too high, people use a product that is free and needed weeks or months of your own free time"
How is he going to recoup anything for his time if you use his product in a way he can't charge for?
Sometime we spend time on a project for the good of the community, and it's ok, because sometimes I give back time, sometimes someone else does and so on.
It's also ok to try to get some money out of your time, if it's desired.
Not ok: use someone else's time to gain personal profit, expect someone else to pay for your actions, etc
How is he going to recoup anything for his time if you use his product in a way he can't charge for?