>when it’s a very common setup to add regular user to the docker group.
As an official configuration? Or in random copy paste guides? The former is very different than the latter. It's not uncommon to disable sudo passwords, but it would be considered a serious security lapse if that were the default on some OS.
The methods are described on the official docker website, not just random blogs or SO pages. There are caveats about security, of course, but it's not truly discouraged.
Adding your user to the docker group is in the official Docker install instructions, I wouldn't call that "random copy paste guides".