There are reasons for the behaviors you see as "dumb."
Linking to 3rd party websites for frameworks is a strategy that facilitates caching and improves security (since security updates will automatically be distributed).
When it comes to "caring" about alternative browsers, what developers care about, is the browsers their users are actually using. If 99% of their users are using Chromium, they aren't going to care about problems faced by the 1% who don't. Why put all that extra effort into supporting such a small minority of users? The cost/benefit equation doesn't support the cost of that effort.
You might say you don't want pages that are built using javascript, and yet, you're on slashdot, which uses a bunch of javascript. And I'll bet just about every other webiste you visited today, also use javascript. Why is that? Because the *developers* of those sites want javascript. Javascript is the plumbing that turns a boring static website, into interactive software. And that's what the developers want.
If it were possible to craft quality websites without javascript, why don't developers do it?