Was interviewing banned?

It is forbidden because it comes under off-topic discussions. :)

Where?

Off-topic

• Advertisements or non-helpful links to 3rd party sites.
• Controversial or divisive topics including religion, politics, or personal issues/revealing details that compromise learner privacy.
• Social groups or clubs, or projects that generate social chats, and other posts not related to coding, in the discussion thread.
• Asking others to “vote up” a project.
• Garnering or receiving votes from a voting ring (groups of people who conspire to vote up each others’ projects). People who participate in voting rings will be banned from community activity.

I am so sorry — I completely missed this email. It comes under "other posts not related to coding", and I forgot to mention that it is also often categorized as spam.
You could also contact Evan Lewis (@lewis.evan) for clarification on whether something is or isn't allowed.