Why Twitter banned the bot that unmasked neo-Nazis. (Hint: Neo-Nazis)

Twitter's number one goal in 2017 was curbing abuse and cracking down on hate speech. But when one intrepid Twitter user tried to help with the problem, the company shut down his efforts.

Yair Rosenberg, a senior writer at Tablet Magazine and reporter, with the help of developer Neal Chandra, had created a Twitter account named "Imposter Buster," Rosenberg wrote in a New York Times op-ed this week.

Rosenberg, who's a Jewish writer, had covered the 2016 presidential election and was a victim of harassment in part due to his stories, he explained in the New York Times op-ed.

This Tweet is currently unavailable. It might be loading or has been removed.

The bot account he created (@imposterbuster) was built to identify racists on Twitter, specifically accounts that impersonated real people from ethnic minorities and were run by trolls. These accounts would join Twitter conversations of high-profile users with racist commentary. The "Imposter Bot" would then automatically join the conversation and attempt to expose the troll.

Unsurprisingly, the bot angered the trolls. In April, Twitter suspended the bot after receiving reports of harassment and spam, allegedly from all those trolls. This month, Twitter permanently banned "Imposter Buster."

The justification for a permanent suspension? The account posted "high volumes" of "duplicative content" and Twitter also continued to receive a spam complaints, according to Rosenberg.

"Just as they duplicitously cast themselves as minorities, they disingenuously recast our response to their ongoing abuse as harassment," Rosenberg wrote in the op-ed.

Rosenberg argued that actions like his are one way to successfully combat trolls and harassment and that Twitter's current enforcements efforts were not feasible.

This Tweet is currently unavailable. It might be loading or has been removed.

In an interview with Mashable, Rosenberg said he hadn't heard anything directly from Twitter since publishing the op-ed.

UPDATE: Dec. 28, 2017, 12:58 p.m. EST A Twitter spokesperson responded to our request for why the account was banned after publication, citing automated mentions as a reason.

"Twitter welcomes the use of our service to counter hate speech and promote positivity, unity, and understanding. We believe this type of counterspeech is a healthy use of Twitter, and a necessary part of a vibrant democracy. Everyone on Twitter must follow the Twitter Rules, including our rules that prohibit hateful conduct, as well the rules that prohibit spammy behavior and automated mentions of other people. We are regularly in touch with developers to help ensure their work fully follows the Twitter Rules and our developer policies," the emailed statement reads.