The Maxx is a body style. Nothing about the body style precludes towing, if you have the right transmission. You have the right transmission if you have the right engine.
A Malibu with a high performance V-6, is not towable because GM mated that engine to the 4T65E transmission, rather than the 4T45E that made Malibu towable. You can find that combination in either sedan or Maxx. Basically it is an Impala drivetrain dropped into the Malibu, for performance.
Malibu SS always had the bigger engine, whether sedan or Maxx, but you could also buy the combination as an option for the LT trim.
The problematic drivetrain was pretty rare, when I was shopping in 2006 the dealer told me I would have to special order it. Remco doesn't even list the combination.
Tom Test
Itasca Spirit 29B