Source?
It's become satisfyingly fast for me over the past years.
> only supporting static documents instead of interactive (tcp) servers.
You can develop dynamic services on Freenet just fine.
It is just done in a different fashion technically:
Instead of hosting the software on a server, and running scripts on the clients' web browser, there is no server/client model. It's true peer-to-peer: Every client is its own server, and the code runs there.
I.e. users install "plugins" for Freenet, and those use the network primitives which Freenet provides to establish dynamic connections and render dynamic content.
So you can have dynamic HTML if you want to. It's just not served by the sites you visit. Instead, things are developed "once and for all" as plugins for all sites and users to use.
So it's kinda like "forced true decentralization". You can't just shove JavaScript down the throat of random visitors of your site. You actually have to go through the effort of making your site's service a real application which people voluntarily choose to run.