Just because Debian thinks that they are doing the right thing, they are in fact, controlling the user's settings through a policy It's just telling you that, as it should.
The notion that it has anything to do with keeping search the default or not is like, such a silly assumption i don't know where to begin.
The feature overall came from a desire of enterprises to manage browser settings. Back then, Google was one of the first to tell you someone was doing that to you so that you knew your organization could see and control your settings.
IE had a deployment kit that let you deploy managed browser settings, but you didn't get told (this changed, eventually, i think, it's been a while)
Letting orgs change the default search engine was an explicit, designed goal, since some wanted to redirect people to their internal searches by default, etc.
There is in fact, another way to do this that is easy and doesn't give the user the same warning, and is meant for software distributors
You can just use master preferences here for this kind of thing and it is meant for this use case.
Google in fact, made this easy and officially supported, despite your claim.
It would likely be pretty silly to make this hard - end users aren't using these interfaces or tools, and distributors always know how to change this stuff .
As HN as grown in popularity, the sheer number of kneejerk reaction comments has unfortunately kept pace (IE the overall percent has not dropped. Even sadder, nobody ever goes back and edits it or replies and was like "you know what, i was probably wrong".
They feel comfortable moving on and doing it again.