You should only need an account on wikipedia not toolforge. Blame all the people who keep uploading pirated movies.
Well then, if not being allowed is the thing that protects us from harm, we're all saved!! /s
Basically you can't openly be evil, and if someone discovers that somebody is being evil they get kicked out. Also i think there is a proxy so you can't easily collect ip addresses.
So its a step above some random website, but ultimately its closer to a third party site then it is to being real wikipedia.
Given you are all on hackernews which is basically a link aggregator for random websites, there is really no reason for this to give anyone pause.