I completely disagree. It's trivial enough to run any minified file through a prettifier.
Even in the first world, on a spotty mobile connection every single byte matters, and some of your users are almost always going to be in that situation some of the time.
Think of minifying as "compiling" for the web. A good dev makes their site performant, and doesn't care about generating readable source code for end-users which 99.9% of them don't care about.
If you want to expose the site's source code to the world in a readable format, then just publish it on GitHub as well, which is the audience that might actually care.
Readable plaintext files are for developers on your team. Not for end users of your product.