I'm only vaguely aware of what goes into web development and programming, so it's hard for me to judge what he says. But I would venture that "lean" web development or programming is harder, not easier. Twain's If I had more time I would have written a shorter letter principle applies. I shared the piece because nothing kicks up a conversation quite like someone passionately, cantankerously making a point.
Web software is the way it is because every browser works a little differently and only very large organizations or very dedicated developers are willing to test thoroughly in all versions of all browsers users are likely to still be using. Everyone else either uses a library or says "IE? Here's a nickel." The libraries are bloated because they try to turn the tangled mess of standards and browsers that implement them badly into something simple enough to be worth bothering to do interesting things with, and that takes a lot of duct tape, bailing wire, chewing gum and plaster.
The author used a bunch of xkcd comics for his article, but here is one that applies to library bloat:
I'm astonished by how timeless some Dilbert strips are.