There are people behind open-source projects. As open source projects increase their audience, the amount of hours of work that need to be done increase too.
If you find yourself to maintain an open-source project that is not backed by a company (like React for Facebook or Tensorflow for Google) and most of the work falls on you — then yes, you need funding.
The reality is that, once you have thousands of dependents projects, you can’t just abandon your project. As for giving the project to someone else: it is time consuming and you don’t have any certainty that you will find a successor.
Then, like Ben said, there is the licensing question: the project can be forked. If you don’t like the ads, make a fork and remove the code to display them. It’s that simple.
Instead, if you want to support the maintainer (and you should) you can use the original project — with ads.
Also, in this specific case the ads were not tracked. C’mon, just an ad when you installed the library. I don’t understand if it is a cultural problem (I’m European) or what, like @kspeakman
Maybe it is just a feel, but seems like most devs idolise the idea of open-source without taking in consideration reality. Open source is great, but at the end of the day: devs are just people, and people have problems and needs and bills to pay.
Open source is not the place where “everything is free”. There are costs, but until now maintainers took care of them.
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