The cables should
all be compatible - Macs implement USB in the same way as PCs. Your only potential worry would be getting OS X to recognise the printer, and even that shouldn't be too much of an issue, given the huge number of drivers already onboard, plus CUPS (Common Unix Printing System) support built in from 10.2 (Jaguar) onwards.
My guess is that the cable suppliers don't mention the Mac OS either out of laziness, ignorance or the fact that the Mac OS just doesn't exist in their world (
this supplier does mention that their cables can be used with Macs, btw).
The HP Printer you mention is supported by CUPS, incidentally.
Here's a link to a 'how to' page in case you don't know CUPS. Good luck
Jx