This is kind of poor advice.

No it's not. It's advice for how to get started. Every player in the history of time tried to barre and got a fwump sound their first time. It's discouraging, especially if you keep trying and find you can't get sound.

You don't need to have a good barre for that chord on other strings.

Right, and I mention it because that is the chord we're discussing. It's also usually the first barre chord a beginner comes across.

You want to get as good at it as possible, on every string.

Completely agree.

intentionally developing a technique where you suck at barring certain strings is not the best idea.

It's not a technique that makes you suck at barring. It's a technique that gets you one step closer to barring and making progress. My guitar teacher taught me that way, I have taught others that way. It was very encouraging when I was a beginner and in no way hampered my ability to fully learn to barre. It made me realize that I too could barre and continue to work until I could barre across the full fret.

This is a grip pioneered by Jimi Hendrix, and he is well known for it.

Or you know, guys like Mississippi John Hurt back in the 20's and 30's.

You don't need to skip any strings.

You do if you're trying to get the same sound as a F major barre chord.