That’s in zero-g. It’s a bit like saying that colonies in North America are impractical because of the dreadful conditions on a 15th century sailboat. A colony - whether on Mars, a Cloud Nine floating in Venus’s atmosphere or a rotating space station - is going to have gravity.
Sure, there’s some unknowns regarding lower gravity. A colony means raising children. And that means bone growth. We’re optimized for doing this at one Earth gravity. We’ve only barely experimented with this at zero G, and we have no idea whether the Moon’s 1/6th or Mars’s 38% gravity would be enough. Which is why Mars is a better bet for colonization than the Moon.
(The Centrifuge Accommodations Module on ISS would have run experiments at different gravity levels. Launch was cancelled in 2005, and its sitting in a parking lot.)
But even for the Moon, science fiction has featured enormous rotating carousel structures on the lunar surface to provide earth-normal gravity for pregnant women and young children. (Isaac Asimov’s “The Gods Themselves” for example.)
