No, "Sick" is not easy to define in humans. In fact it's even harder than it is on computers. Plenty of people get misdiagnosed and held when they don't need to. Plenty of people miss getting diagnosed and go out and spread it around. There are also plenty of cases of political manipulations for nationalistic purposes. (China deported a lot of foreign nationals during the swine flu scare when there was no evidence of flu.)

But all that does not mean that quarantine is not a good practice. It is usually the best practice available given the knowledge at hand. Don't confuse principle with implementation. If you don't like the implementation, then go fix that. But it would be a mistake to think that poor implementation invalidates the whole principle.

You missed the point. It's not punishment.

It's quarantine. If a person gets sick with a contagious disease, it may not be their fault and you probably don't want to punish them. But for public safety, you do need to contain them until they are no longer dangerous to others.

The same applies to sick computers. If it is spewing viruses and malware then stop it, whether the person who owns it was doing it intentionally or not. You can forward all traffic to a local ISP web sight that informs them of the problem and directs them to appropriate ISP approved scanning software or other solutions available within the quarantine zone. If the user does not trust the ISP, fine. They can go clean their machine themselves.

Whether you trust the ISP/Government to have the right motive is a separate issue. But quarantine is an established procedure for humans, and it's not that different here.

If you are comparing AOL to the internet and modern ISPs, then you are completely correct.

The thing with AOL is that it was around *before* the internet and those other ISPs. AOL came around in the age of the BBS.
Everything was dial-up. Mail was tossed and copied around node to node. It was almost all local due to phone charges. What AOL did was make a national BBS, and put in local dial-up access points in most local calling areas. It was bigger than any other BBS of the time. It offered mail to any other AOL user, and mail bridges to most other networks (like compuserv). They had a GUI when everyone else was text based. You can't call them stupid for being the biggest provider in their market. Their problem was that the market changed.

When the internet finally did grow up, AOL was already big. The problem is that the internet changed the online equation. Access became commodity. AOL had to rely on content. (That's why the TW deal). But eventually, the internet had more content too. So AOL is a leftover giant.

I guess we could just expect them to rollover and die because they are outdated. But it's funny how many people don't want to do that, regardless of how outdated they are.