It seems to me a weak thesis. Regardless they earn money, damn, even without actually staying in the apartment they earn money. We don't know how much tenants precisely earn and they don't know how much a tenant earns in Prague or other cities outside of Barcelona. To make this sort of protest they should know how much Leora earns even if she do nothing, but unless they chat with Leora personally they can't know for sure.
Take for example Lubna. Lubna has been doing nothing since day one but going to work to the sex club and nothing else. Should she earn as much as Leora based on what? she already has a job outside rlc which, in her words, is paying her a lot. Maybe even more than being on rlc. It will be the same for Nadia too. Milena doesn't have a job but still doesn't do anything in the apartment since day one, why should she earn as much as Leora knowing she'll be there for a little while on rlc? (we know that Milena won't be there for a whole year on rlc for the question of her son or daughter.)
Then you mention Stella but which participant was Stella? Stella is remembered because every time she came back to rlc she was only there for a couple of months in which she did practically nothing. Only the last time she was on rlc did she show something, then the other times before she was basically remembered as a good for nothing. How did she expect to earn as much as a participant who has been on rlc for 10 years if in the few months in which she participated on rlc she did nothing?