Honestly I could not understand this point. How could just playing on physical casino will assure you that you are not into a rigged environment just due to more other people are watching you and your gambling activities? If you are into a rigged games without knowing then people around you also might be not aware about what is actually happening.
maybe he means legitimate game is that we are dealing physically while in Online there are instance that we will be cheated by the site or will be scammed upon withdrawals just like what most cases being put here in this forum.
There are still instances of casino games being rigged though. It may not be obvious at first glance since there is a lot more difficulty in spotting rigged games irl, but there are quite a few ways to rig games like that. At this point, the only thing you can accuse of online casinos is their scams of withdrawals as their provably fair system, but irl casinos have the leisure of rigging literally everything. From slots, to dice, to cards, they have the capability to do so if they wanted to. Ofc, getting caught is a different issue, but the point is, Irl casinos have higher chances of having rigged games, especially if the casino itself is a not so trusted/infamous place.