Try reading a Medium article on slow internet connection (such as EDGE), then compare with a plain-text article like http://motherfuckingwebsite.com/.

Is there a full-featured, usable, free, no-code, no-sysadmin blog platform with performance akin to motherfuckingwebsite.com ?

I haven't used it (I prefer to write my site myself), but perhaps https://bearblog.dev/?

Nice, that does fit the bill!

Note that it does not include custom domains or image uploading on the free plan, but you can upgrade for $29 (lifetime), which gets you:

    Custom domains (this is time-consuming)
    Image uploading (due to the cost of hosting images)
    Email subscriber lists (since it gets complicated)
    Beta features (since they aren't ready yet)
    You can upgrade for $29, flat.

The editing interface is just a textbox where you paste markdown; doesn't seem there's a github integration or anything like that, which is too bad.

Soft paywall for some random guy's blog. Uses 40mb of artisnal javascript to display a basic text document with a few images maybe. Hostile to the open web.

I stopped copying my articles there, some time ago.

I stopped when I posted an article, and Medium decided it was so good, that it deserved a paywall.