Their behaviour can too easily be constructed into a very negative picture.
I can see Crossfit going one of two ways:
Either it will reach a high water mark and settle down to a steady-state condition. More people are coming into Crossfit, but in many markets there's a saturation of affiliates. Gyms with overheads like full-time, well-trained coaches will be partly driven out by cheaper operations with a CF1 certificate.
Alternatively, someone will construct a successful legal argument that Crossfit is a franchise operation. A subsequent class action lawsuit will turn them into a smoking hole in the ground.
On the upside, millions of people will have learnt that exercising is fun. That is definitely a positive outcome.