Warning spammers or deliberate ToS violators is now a matter of decency? The company admitted they knew they were in the wrong and that Twitter would eventually shut it down. I'm not sure how it's remotely a matter of decency when it comes to intentionally malicious actors.

On reflection, it's almost certainly because the app was getting some press and Twitter wanted to make it clear what the situation was. Versus allowing the offender to pretend it was another issue or spin it against Twitter (though they seem to be trying!)