WASHINGTON — It usually doesn’t take much to get people on the internet worked up. To get them really worked up, make the topic internet regulation.

In the week since the Federal Communications Commission released a plan to scrap existing rules for internet delivery, more than 200,000 phone calls, organized through online campaigns, have been placed to Congress in protest. An additional 500,000 comments have been left on the agency’s website. On social media sites like Twitter and Reddit, the issue has been a leading topic of discussion.

In some cases, views on the sweeping change, which would repeal landmark regulations meant to ensure an open internet, have turned into personal attacks. The agency’s chairman, Ajit Pai, said threatening calls and emails had poured into his home and his wife’s work. An image of a protest poster with his children’s names was posted online and spread widely. Ethnic slurs aimed at Mr. Pai, whose parents immigrated from India, littered his Twitter feed.

There are also echoes of the 2016 presidential election, with accusations that not all of the reaction is coming from Americans. The federal agency is for the first time dealing with a powerful technology foe as automated software, known as bots, appears to have sent many comments to the site, according to data researchers.