No one’s gotten into the actual “why” that I’ve seen. This goes back to the early days of the internet, or even computers, really. In the ’80s and ’90s computer screens were much lower resolution than today. The finer details of traditional typefaces were often lost. There was a big push to simplify and optimize for the screen. This also impacted the early days of the web. I remember the advice for amateurs was to design your pages for small resolutions screens, windows that were only 800x600 or even 640x480, which would work on a standard definition TV.

I remember the defaults in web browsers in the late ’90s were often badly spaced Times New Roman. People would try to code better fonts when they could define them, but they were still largely in the mindset of using fonts optimized for low-resolution screens. Worse, in the early days there were no web fonts that could be imbedded in web pages, so you’d have to try to pick a font likely to be on your readers’ computers, which usually weren’t great.

Nowadays basically everyone’s devices have high-resolution screens, and we have embedded fonts, so we don’t have to live our lives that way. Still, that decades-old advice echoes through in modern designs. And there are a lot of bad free fonts out there, with people unwilling to pay for a font or put in the effort to find a good free one.

As for what you can do? You can’t force everyone to change, but you can be the change you want to see. Encourage people to learn about good typography, which is not just fonts! Make smarter choices in the written work you produce yourself to show others the way. And to get by for now, change the default fonts the devices you use if possible, or individual apps or web browsers. You can even install browser extensions like Stylus to replace a page’s style sheet with a different, better one.