[fabian2k]

This is not the spam or vandalism counter-measure, those work differently and only block posting to the sites. And you can avoid them if you establish a reputable account, they won't affect you anymore then.

[jbentham]

If it is not to block spam, or vandalism, or denial-of-service attacks, then what is the purpose of this new policy?

To your other point, how can one establish a 'reputable account' if it is not even possible to access the site in the first instance.

[floatingatoll]

Reputation is a feature of identity. Tor users are, by definition and intent, unidentifiable. Opting out of identification naturally opts one out of reputation, as is the case in reality as well — for example, Anonymous using Guy Fawkes masks to prevent reputation from being associated with their citizenship identity.

I don’t understand why Tor users would be interested in reputation at all, given the implicit identification it requires.