Is the point of free software to create as much variations of a program as possible?
I'd rather see that useful changes are merged upstream, or projects are forked. If this had happened, you wouldn't even need to patch, and this would save an enormous amount of manpower that is wasted on trivialities.
Distributions exist to provide software that all fits and works together (e.g. providing the correct versions of dependencies). Sometimes patching is necessary to make things work.
Here's two examples of how distros patching software has been helpful for me.
1) SquirrelMail (abandoned) patched to work with PHP 7.3 thanks to FreeBSD contribs
2) Abiword patch builds in the AUR that fix a broken default install.