I think that's pretty normal conflict of interest language. Seems pretty reasonable in general. You do see broader permissions around things like developing open source software at some companies but they're not common.
At least as a practical matter. Some large companies (in particular) may have draconian policies about doing moonlighting but it's probably not a big deal generally as long as it's low-visibility.
I avoid obvious conflicts of interest. And for any unpaid and pizza-paid advice/minor work for people I do it quietly.
But that stuff is pretty simple relative to a (minor) real side-gig which I had (shareware back in the day) but was pretty much orthogonal to my day job and my manager knew about.