You're a little quick on the trigger finger there partner. Not everyone is a "shill", keyword pumping for the competition. I created an account and posted here because I don't think your opinion is well formed - or better, it is misplaced.
Not that it matters, but In all likelihood, I know far more about "seo" and "spam" than you do... it (internet based marketing) is my livelihood and prior to that I owned and operated an IT consulting firm (~20 years). I have both feet firmly planted in both sides of the game.
-I never said that "major" DNS providers don't filter. Of course they do, each having their own reasons (good or nefarious). I said, if you don't want to have your results filtered, then use your OWN DNS root hints, or DNS provider that agrees to no filtering.
-I never said that search engines and DNS providers don't filter what you search for - of course they do, it is their prerogative.
Those providers are no different than the DNS filter in your product. They intercept a query and act upon it with a filter (for whatever reason, good or nefarious). You just don't like WHERE the filters are applied (I.E. your software or somebody else's).
I think the issue here is misplaced anger toward "censorship" and confusion about DNS architecture, or where it fits in. You appear to want to elevate DNS providers to some moral or enforced standard above that of search engines or other products. The problems is that "DNS Providers" are not a governed part of the architecture, and even if they were, only countries and entities willing to play nicely would adhere anyway-leaving us in the same boat.
You mentioned the phone book analogy - There is no "phone book". There are "phone books" - each localized or curated for a reason, from White Pages to Yellow Pages and countless directories in between. Some specific to localities, some to business verticals, and others to carrier's own subscribers. DNS "providers" are like phone books in that sense. The difference is, that we can go a level above them and to the root servers. FWIW - there is no "phone company" analog to this, even if you collected every carriers database and centralized it!
The cure to what ails you (as i have repeated) is that we in fact DO have the ability to see unfiltered DNS quires by starting our query at the root level. Anything in between has (will) curate the returned results. There is no jurisdictional or enforcement mechanism that could ever change this. It is not they way the system is built. To argue any differently is to be naive to how it all actually works and what can or can't be controlled. Be happy we have that at the DNS level, as from the search perspective there is no "index" of the entire "internet" to use if you don't like the filters your chosen search provider applies.
I don't disagree with your sentiment - I am just pointing out that it is misplaced. The large providers of the world are shaping the very fabric of society by carefully curating what we see and read, from politics to social behavior and everything in between. I don't like it either, but DNS itself is not the culprit. Be angry at your provider, not the mechanism.