That is clearly not the case. The city has offered to rent to the Scouts for $200,000/year. So clearly, the issue is not legal prohibitions against renting city land to organizations who "discriminate". Something else is at play here.
I wasn't as clear as I should have been. According to the article the city can't continue to rent to an organization that discriminates at the dollar per year it had been charging. Apparently it can rent to anyone so long as they're paying fair market.