They are JPEGs, even. How sacrilegious.

to be fair, mobile users are probably grateful of that

Not me, as they are all in different resolutions, having to zoom out, to zoom in, and zoom in again. Simple text would be better.

The author collected these from a Twitter thread of theirs, in which the artworks had to be shared as images. Converting all back to text would be laborious.

Each image is a link to the original source. It was a simple matter of copying and pasting the text instead of the image.

But then you wouldn't see them correctly on mobile browsers.

If you're referencing line wrapping, wrapping the <pre> in a <div> with just two styles would work:

    display: block;
    overflow-x: auto;

That would allow the <pre> to overflow to the right and let the user scroll over.

Isn't it fair considering how easy they could be broken due to the difference between environments?

Put them in `<pre>` tags and they should render as monospace and the whitespace as-is at least.