Don’t think I’ve ever seen anyone suggest setting text-justify. It’s one of those properties that I could imagine having been used in anger and with cause (justifiedly :P) less than a hundred times in total, though the true number is probably higher than that. Anyway, in this case it won’t change anything, because the text is English, and the default value of auto will be equivalent to inter-word. (If the text was Japanese, it would actively harm things, because auto would be equivalent to inter-character, and you’d mess that up.)

Anyway, in all current browsers, `text-align: justify` does greedy text layout, where it fits as many words in each line as it can before wrapping. This is technically trivial, but visually inferior to Knuth-Plass line breaking, which tries to find the most visually-pleasing place to break lines. Look at the screenshots of https://github.com/robertknight/tex-linebreak to see the difference. It can be rather stark.