> some users will attempt to remove undesired behavior,
Surely. But a link in a comment to a supporter who helped finance the project is not really "behavior" is it? It is not part of the program that executes.
So it is not "undesired behavior" since it is not behavior at all.
But is it "undesired" in other ways?
If you put in a copyright notice into the source code, that is a kind of advertising for whoever's name is in it. Often comments contain links to the website of whoever maintains the source-code. Is that undesired? If not then what would be so undesirable about putting in a link to the website of whoever supported the project financially.
And if they paid for that, they would be supporting the project financially. And in the end isn't that what we want, financial support for Open Source projects?