or they want the marketing benefit of open source, without the loss of revenue when inevitably someone makes profit off their open source code in a way that the original authors cannot.
I think it depends a bit on the real intention. If the author intends to grow their project to a business and is upfront about it, there is nothing wrong with that. After all a sustainable business would imply sustainable project.
The misfortune happens when the concealed and public intentions are not aligned.
there's intent, and then there's action. I personally don't care for intent. I care about action. The actions of some open source projects are in line with the intent that they want to use the PR generated to gain revenue. When the open source license fails to achieve such goals, they complain (like elastic search did).
or they want the marketing benefit of open source, without the loss of revenue when inevitably someone makes profit off their open source code in a way that the original authors cannot.