I think it's pretty clear cut and something that would be easy to define, such as having collected a paychqeue playing in a professional sports league or organization. Yes that means no Ray Ferraro. I don't know about the Rock, but easy enough to lump pro wrestling in there.
I think the regulation actually governs any celebrity including influencers so it is a moot point but for the sake of discussion I disagree with you. I don't see how it is "pretty clear cut."
If the rule is "having collected a paycheque playing in a professional sports league or organization" does that include the CHL? In hockey the CHL is considered an amateur hockey league but the players do collect a "paycheque" and the business model really isn't different from what is considered a professional sports league or organization.
I'm guessing that you aren't aware of Dwayne Johnson's CFL past. I would argue that "professional wrestling" like WWF/WWE is more entertainment than professional sports.
Most of that you don't need to worry about because these are gambling outlets targetting specific sports and will want premier players from those sports for those adds. So Wayne Gretzky, Conor McDavid, yes. Ray Ferraro, no. Dwayne Johnson and Oscar De La Hoya... what they heck would those guys be doing in Canadian provincial gambling adds?
Regardless though it's up to the province of Ontario to define their guidelines for advertisement as they see fit and if there's any issues then that can be brought to the supreme court. Let's just call this 'civics' rather than the forbidden 'p' word.
My understanding is that the regulation bans "the use" of athletes. It doesn't matter if it's a national, international, or Ontario-specific ad. Have you seen Jamie Foxx and Kevin Hart sports gambling ads? I have. I'm sure you're asking what are their ads doing in Canada?
The point is that there are "former athletes" who have gone onto become famous for what they do in their post-athletic careers. Dwayne Johnson is one of the most recognizable actors in the world and is also an investor. I don't think Dwayne Johnson has invested in sports gambling specifically but other former athletes have. If the football leagues (including the XFL) wanted Dwayne Johnson to be part of a sports gambling ad or if he wanted to join his buddy Kevin Hart in a commercial his ad can't be played in Ontario simply because he's an ex-athlete.
But again, I think the regulations extend to "celebrities" so the point is moot but if it's just under the ex-athlete definition I don't think it's as clear cut as you think it is.