In this case the clothing was for sale, it was a line of bike wear for anyone to buy, associated with him. Kind of like buying a hockey jersey with a players name.Sponsorships are kinda a big deal in the cycling profession. So walking around in the gear provided only to sponsored professional at a sponsored event when you are neither a professional nor sponsored is extremely odd.
Imagine you bring a date to a business event and your date is walking around with you, introducing themselves to your coworkers and boss, and wearing a name tag pretending to be CEO, and not as a joke. It’s kinda like that.

Rapha unveils geology-inspired Colin Strickland Strata gravel clothing range
The 2019 winner of the Dirty Kanza gravel race partners with British clothing company for eye-catching collection
ETA but as posted above, perhaps forbidden by contract...?