From the article:
>We need to send a strong message to the world that the Internet has thrived under a decentralized, bottom-up, multi-stakeholder governance model.
While that statement was made by a Republican Congresswoman, I see no reason to think that it doesn't accurately represent the thoughts of most of the House - including Democrats - because, as she points out, it is a multi-stakeholder model. Some of the proposals before the ITU, the very ones the House is united against, would put significantly more power in the hands of the federal government - not less.
Why do Democrats oppose it anyway? Because they aren't fascists. Sorry to be the one to have to tell you.