This improves other search engines as well, not just the Google universe. I'm sure even an opensource, peer-to-peer search engine will have similar issues of content farm content and gamed pages if it becomes large enough to compare with search engines like DuckDuckGo.
On the other hand it is absolutely ridiculous to conflate the difficulty of occasionally adding a domain to a local filter, and assisting to build a random unproven search engine. People volunteer their development effort for projects they personally find interesting or challenging. If you want more developers advocate for the project don't try to scold people for wanting to spend a small amount of their time refining a solution that works for them.
On the other hand it is absolutely ridiculous to conflate the difficulty of occasionally adding a domain to a local filter, and assisting to build a random unproven search engine. People volunteer their development effort for projects they personally find interesting or challenging. If you want more developers advocate for the project don't try to scold people for wanting to spend a small amount of their time refining a solution that works for them.