Citation on o2/Telekom/etc blocking domains?
> I also know that they collaborate with lawyers going after individual p2p users.
Kind of hard not to do if you're legally obliged. But not per se a privacy violation and not a matter of snooping on content.
> And I know it has a history of serving advertisements on domains that don't resolve (something I opted out of years ago).
> Ok but again not really a major privacy leak, just stupid/bad/user-hostile practice.
> I also know DNS traffic data is routinely shared between different nation states and that this practice has little or no oversight.
And who is the main party spying on/in Germany? Snowden leaks tells us the NSA, with active but idiotically unaware cooperation by the BND. So you're giving data directly to a US cloud provider instead.
Parties, plural. A better question would be who isn't spying. I live in Berlin. The Chinese, Russians, North Koreans, US, UK, Iranians, etc. all have big embassies here and there is a lot of diplomatic traffic and it of course features frequently in popular fiction on espionage. Also, there are lots of political refugees from all over the world living in Berlin. E.g. Ai Weiwei lives somewhere in my area and I've seen him on the street a couple of times. I live a kilometer away from the HQ of the German secret service.
I have no illusions about Cloudflare. However, unlike my ISP they are big, pretty competent, generally under a lot of scrutiny, and have a very big incentive to not get caught with their pants down contradicting what they say they do in their contracts, terms of use, etc. Not exactly ironclad, I know, but definitely a step up from O2's combination of indifference, incompetence and tendencies towards actively not caring one bit about their users privacy.
If you have a laptop and configure your DNS automatically, you are using whatever DNS is configured by hotels, airports, coffee shops, etc. You have no privacy whatsoever when it comes to DNS requests and you have no control over this until you manually configure your DNS (which most users don't even know how to do). The default configuration of laptops is to use whatever they are told to use automatically. In most places the only safe assumption is that multiple nation states are actively monitoring and aggregating every single DNS request you make and the practical reality is that that is actually exactly what happens.
The sad reality is that ISPs in most places don't lift a finger to protect the privacy of their users and actively facilitate policing, censoring, and monitoring of their user's DNS traffic; even when they are not required to (which they are in most places). Your trust in them is completely misguided.
I live in Germany. I know that my ISP works with the German government to help them censor me accessing certain websites by blocking DNS. I also know that they collaborate with lawyers going after individual p2p users. And I know it has a history of serving advertisements on domains that don't resolve (something I opted out of years ago). I also know DNS traffic data is routinely shared between different nation states and that this practice has little or no oversight.
In so far they are not actively sharing data (which they are), they can also be relied apon to be generally incompetent when it comes to operating and securing their infrastructure and you'd have to assume that foreign intelligence agencies have been actively helping themselves to whatever information they can extract that way for decades.
If you are wondering, my ISP is O2. I'd switch but Germany has a state protected ISP oligarchy and the other ISPs are not really much better.
Mozilla protecting users from their privacy being violated like this by default is a net improvement in most places in the world. Anyone who cares about their privacy enough already configures their DNS manually and probably also uses a VPN and can continue to do so. But for those not capable of figuring this out, this is a massive improvement of their default level of privacy. The status quo for that is that they have none whatsoever in most places when it comes to DNS. It's hard to do worse than that.