He's speaking from experience. But, if your circumstances aren't exactly the same, the outcome may be different.
Credits pages in software, accessible from the main UI, used to be very common, and having names there -- or embedded in source code -- doesn't violate a user expectation.
Server software sending 'Server:' headers also doesn't violate user expectation, though some people prefer to turn these off.
Custom headers that cannot be turned off have a higher likelihood of violating user expectation.
To the OP: in open source projects, some users will attempt to remove undesired behavior, within the rights afforded by the license, but these exercises of copyright can interact adversely with trademarks and other brand protections, and with the surrounding (human) infrastructure and information-space around a project (e.g. names, URLs, references to services, secrets).
Your attempts to reconcile such a situation are nontrivial, and both inaction and action have a high likelihood of resulting in bad press (e.g. user confusion about fork, or heavy-handed enforcement). The harm will persist long after the original situation has been resolved or mitigated.
> 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?
Credits pages in software, accessible from the main UI, used to be very common, and having names there -- or embedded in source code -- doesn't violate a user expectation.
Server software sending 'Server:' headers also doesn't violate user expectation, though some people prefer to turn these off.
Custom headers that cannot be turned off have a higher likelihood of violating user expectation.
To the OP: in open source projects, some users will attempt to remove undesired behavior, within the rights afforded by the license, but these exercises of copyright can interact adversely with trademarks and other brand protections, and with the surrounding (human) infrastructure and information-space around a project (e.g. names, URLs, references to services, secrets).
Your attempts to reconcile such a situation are nontrivial, and both inaction and action have a high likelihood of resulting in bad press (e.g. user confusion about fork, or heavy-handed enforcement). The harm will persist long after the original situation has been resolved or mitigated.