This news report shows an argument in Venice, California between a woman with a unique treehouse versus the “McMansion proponents” suspected to be behind opposition to the treehouse.
We don’t get much background about these “McMansion proponents” but it does strike me as an effective moniker to neutralize the opposition. Who wants to be known publicly for being a “McMansion proponent”? Even those who like big houses or think property owners should be able to have teardowns wouldn’t loudly say they like McMansions. They would want to shift the language to something like “luxury house” or turn the conversation back to the topic of individual rights. Additionally, using the term McMansion often implies outsiders who want to build big houses and change/destroy the neighborhood with their oversized homes. It suggests this is an us vs. them battle, the humble homeowners who just want enjoy their neighborhood versus monied people who want to construct their private paradises.
Regardless of the outcome of this, it is hard to imagine a more effective negative name to use than “McMansion proponents.”