You`ve honestly never run into a blocked site? When I was working for a major adult tube site I would investigate perverts (because LE was useless) who posted terrible content to the site. NONE of the sharing sites these people used were ever blocked. In all my years working on adult websites I never ran into an adult-oriented site that was blocked. Not even the obviously illegal ones.
The sites I found to be blocked, while using Rogers, were alternative media sites that spoke about things that don`t fit the status-quo. I would attempt to follow a link and get Rogers-branded pages telling me there was a problem, or sometimes nothing at all, not even a 404 message. I would go home and see it working fine on Bell. I thought that`s got to be a network issue that resolved, but again it would not work on Rogers so I asked friends and associates in the US to look at they would see it while I do not. I was able to determine through this process of checking the same URL from multiple ISPs at the same time that one of those ISPs was not resolving the DNS.
If you know how DNS works then you can easily see how the ISP could screw that up, or intentionally blacklist an IP or URL.
All .com`s (domain names) are just a pretty face for a number, such as 192.168.1.1. That number is called the IP address, and it is where the domain name points to. When you type in https://terb.cc the website you see is located at 69.90.76.167. You could put an http:// in front of that and prove it.
Firefox knows where the domain name points to because of domain name servers, DNS. If you are using Rogers then Rogers is the door you go through for all your web activity. You type in a domain name, firefox asks Rogers for the corresponding IP, Rogers answers, Firefox makes the connection, then the website loads.
If Rogers` DNS points to the wrong IP then you get the wrong site. If they list it, but block it, you get whatever page they redirect you to, such as a Rogers-branded error page, or they can just throttle the throughput on it.
And that my friends is the proposed future of the internet without net neutrality. Your ISP will offer branded services and give you great throughput on it, but the competing services can be blocked or throttled to a point where you can`t stand to use them, and you default to your own ISP.