Most people don't really know what's good for them...
Justification falls apart on mobile web where too few words can fit on a line and then you get big gaps between words.
On longer lines, a ragged right edge makes a good visual guide to keep the eye on the right line while reading a wide justified paragraph is hard to keep track of while reading.
https://medium.com/@meetchopz/10-bad-typography-habits-that-...