Though it sounds like the normal automated account creation flow is also blocked from that ISP. That could be more problematic and discourage editor account creation.
But they're not blocked from editing — they just need to be logged in. Wikipedia users can use their existing account. New users were given a human-reviewed path for directly creating an account, apparently out of necessity.
Yes but then you have to wait in a queue for someone to create the account for you. That is, if they don't deny that too. Also they require your email address for this process.
It's just more and more barriers when all you want to do is quickly correct some information in an article you read. Very frustrating and counterproductive!
So if you're on the go, and you're the type of person who wants to edit wikipedia, you'll be prompted to log in. If you don't have an account you would need to create one which probably involves waiting 'til you're back at home or the office. That's ... not that bad, I imagine they didn't do it randomly but because they had a wave of bad-faith edits from EE users.
There are over 26 million EE users. Some of them are going to go to Wikipedia and make malicious edits because some people are just like that. But punishing everyone else for it seems like overkill to me.
Blocking anonymous editing from a range of IPs to combat malicious editing seems ok in my book since they allow alternative means.