I don't use any of the CA lounges but this does sound like a silly rule. On the other hand, if someone brought smelly and/or messy food in then I'd absolutely want them kicked out to avoid any problems. Seems like the rule could be rewritten to say something about messy or odorous foods. I guess that's considered too complicated to the people who write the rules.
There's nothing preventing people from bringing that stuff on board the train to consume at their seats.
However, if something is truly offensive, I think a conductor has the authority to order it gone - similar to the "offensive hygiene" rule. I remember when I was on vacation in Thailand, there were signs in many places that this particular fruit wasn't allowed. In Singapore, it's not allowed on public transportation.
It's called durian, and I've never willingly eaten any. I once mistakenly ate something that had some natural durian flavor, but spit it out almost immediately. I have smelled it from a distance and can't understand how anyone could willingly put it in their mouths.