AWG has nothing to do with insulation. It is a wire gauge, after all. Read JST XH datasheet and you'll find compatible wire AWG.
XH housing supports 3 sizes: for 26~22, 28~22 and 30~26. Therefore Wikipedia correctly provides the full range as 30~22. The auction listing is different from all of them so either it is a mistake in text or you've bought some 3rd party product with unknown properties.
Insulation OD is also provided in datasheet. The design of crimp contacts can accept quite wide range of insulation thickness, the limiting factor is usually the size of the opening in the plastic housing. Although the reliability of the crimp will be reduced if you use diameter outside of the specified range.
In my experience these connectors easily accept 22 AWG with thick silicone insulation.