The main reason this argument exists is because of Roblox being difficult to compare with other platforms. For the most widely used platforms/engines/storefronts in the industry, the main payout model is that the percentage (for storefronts ~30%, smaller for smaller platforms, for commercial game engines ~5%) or fixed/variable fee (per month or per seat in the client organisation) is taken as payment for using the distribution platform or a royalty for using the game engine. The remaining quantity (60-80%) is given to the developer of the game.

To make it clear, this is not profit! Any money earned after paying the storefront and the engine still needs to be spent on server hosting & maintenance, as well as moderation & legal compliance if a game is popular enough to need it. There also is a risk that the expenses taken away in this area could outweigh the revenue and the developers end up with a loss. Unless all expenses are negligible, the resulting revenue isn't just for the developer to keep.

Roblox pays for an experience's server hosting, maintenance, moderation, legal compliance, discoverability, engine development, app store fees, etc. As results, there is no risk of such loss, though Roblox's operating costs are much higher than a typical game storefront. I would consider these costs as developer operational costs. As far as I can tell, the key difference is the fact that one party is having their costs paid by another rather than one party giving another the money to pay for it themselves. This, to me, is an arbitrary distinction.

Other platforms don't have clauses that need to differentiate between money given to developers as profit and money given to developers as infrastructure/upkeep costs because these other platforms don't deal in the kind of broad integration that Roblox has from the storefront to the datacentres. In almost all cases, the final payout a developer gets from Roblox is pure profit.

The services Roblox is selling might not be using a standard industry pricing model, though it's still very clear and not at all deceptive what the product is the developers are paying for and what the profit share is after operating expenses have been paid for on their behalf.