A ranking of every Weezer song includes using the term “McMansion” for the second-worst song on the list:

204. “Beverly Hills,” Make Believe

To this day, Weezer’s highest charting single – which makes sense, as it’s about as close to the lowest common denominator as the band has ever sunk. A lumbering monument to the pursuit of wealth and luxury, “Beverly Hills” matches its vapidity of message with a McMansion’s worth of painful musical ideas: the clumsy half-rapping of the verses, the annoying “gimme, gimme” rejoinder of the chorus, the talkbox solo of the bridge. Even louder than the caveman thud of Pat Wilson’s opening drum salvo was the sound of dyed-in-the-wool diehards stampeding for the exit, finally ready to accept that the glorydays of Pinkerton weren’t coming back.

The most obvious use of the word here is to suggest the song has a lot of bad ideas. McMansions are criticized for their size and their poor architectural ideas.

But, there could be more here in this paragraph. A few quick ideas:

1. Beverly Hills is a wealthy neighborhood with a lot of big houses. Are some of them McMansions? McMansions are connected to displays of wealth and excessive consumption.
2. The reference to “the lowest common denominator” could be linked to the critique that McMansions are vapid and mass produced. They are not real mansions; they are attempts to mimic higher quality construction and more architecturally pure mansions.

All together, the use of the term McMansion here does not refer directly to the actual homes. Rather, it highlights how familiar the term is in order for its use in a music review to highlight abstract ideas.