I agree with them, nothing wrong to ask for a donation to keep the lights on. At the same time, it needs to be possible to disable this banner for enterprise deployments
It's open source so I'm sure there is a way. But maybe then the enterprise deployments can't depend on the freely provided binaries and hosting associated, and will have to build the project themselves and handle distribution.
If there's anybody who should pay for their software, it's enterprise. They should be able to disable the banner by paying a fair price for their office suite.