Does this stop their kids from typing on their keyboard?

(And anyway, surely viewing a web page counts as an interoperable web standard already?)

Twitter is a walled garden service and is hostile to both their users and to people in the developer ecosystem. It does not even pretend to interoperate.

While this doesn't address the number one issue (the kid on the keyboard) it does provide a certain amount of accountability and transparency into how a public sector agency pushes their communications out into the world / digital commons.

I still don't see how it prevents children from accessing their parents computer.

they would implement the system such that two toddlers no less than 15 feet apart would need to type the identical gibberish characters into two terminals simultaneously in order for the tweet to be published.

Build clients for it that mandate biometric access following already-existing government data security standards.

Should they self-host TV stations, newspapers, and radio stations? Why should internet media be any different?

Simple. They can control TV stations & newspapers. Facebook & Twitter, not so much. At least, not yet.

I question why social media is a requirement in the first place?

Agree. The dependency on private services is not appropriate for officials or agencies communicating with the public. This is especially problematic when you consider that the public's responses will be subject to content moderation and censorship based on Twitter's whims.