A few minutes ago, my ad blocker broke the login form of my cellphone provider. A non-technical user would probably not think to turn off the ad-blocker, and would assume that the website is broken. Not being able to log into your phone provider (or bank) is a pretty serious inconvenience which should not be taken lightly.

If a login form breaks because of an ad-blocker then the site is broken. Ad-blockers have a bigger market share than most browsers!

I agree that the website is the thing that is broken. Their code looked like this:

  reportToTracker('userActionSubmit');
  submitForm();

The first line threw an exception. They should have surrounded that line with a try/catch block. And they should have tested against popular adblockers as well as popular browsers. But it's also within their right to not care about adblockers, and live with the consequences of upset customers. Unfortunately, very few customers will complain, so this becomes an externalized cost which the website owner never sees.

Practically speaking, if I install an adblocker on my friend's computer, and their mobile provider website stops working, then I personally feel some responsibility for making my friend's web experience a bit worse.

>Ad-blockers have a bigger market share than most browsers!

Browsers adhere to standards. Meanwhile, there are hundreds/thousands of filter subscription combinations that people use, along with several adblocking extensions.

>Changing DNS will break notjing. Neither will blocking referrals, blocking trackers, blocking ads. In the rare case it does,

>break notjing

>In the rare case it does,

Aside from the obvious contradiction in those two sentences, there's also the issue that adblockers work so well that most people won't think of it when stuff's broken. This problem's only exacerbated by the other addons such as httpseverywhere (known to break sites and show scary warnings).

Cloudflare's 1.1.1.1 DNS server has recurring trouble with the (non-Cloudflare) CDN used by Macy's for their website and mobile apps. I last observed this failure in February 2019. Changing DNS absolutely can break things.