I would. I have tons of open source contributions. I haven't felt the need to spam 1000s of developers and millions of logs with ads for myself.
35 years of open source and so few self promoting ads suggest most open source devs have been fine without the spam. There are plenty of other ways to try to get funding for your open source work than spamming people.
It does not take much imagination to see where it will lead. A single npm install like babel or eslint or jest or mocha that have many dependencies will spew out 10s of 1000s of lines of self promotion ads. That's untentible
In the specific case of core-js I think the author was in dire need for financial support after an accident - github.com/zloirock/core-js/issues...
Again, it seems more like a cry for help instead of a grab for money. Situations may arise when reaching out is the only option - the alternative would be to abandon maintaining the project completely. And very few developers are also marketing-savvy enough to find alternate sources of income that will allow them to continue their work.
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