I’ve never heard of servant oriented, but I understand the point. Browsers process and render whatever the server returns. Whether they’re advertisements that download malware or a long rambling page on whatever I’m interested in now, browsers really don’t have much control over what they run.

I'm not sure what you're talking about.

1. As we're seeing here, browser developers determine what content the browser will parse and process. This happens in both directions: tons of what is now common JS/CSS shipped first as browser-specific behavior that was then standardized, and also browsers have dropped support for gopher, for SSLv2, and Flash, among other things.

2. Browsers often explicitly provide a transformation point where users can modify content. Ad blockers work specifically because the browser is not a "servant" of whatever the server returns.

3. Plenty of content can be hosted on servers but not understood or rendered by browsers. I joked about Opera elsewhere on the thread, which notably included a torrent client, but Chrome/Firefox/Safari did not: torrent files served by the server weren't run in those browsers.