I don't understand why. People spend money on other things besides housing. Because people spend money on multiple things, it doesn't really make that much sense to say that our index of inflation should track be one thing. I mean, if the price of food and healthcare tripled, I think you would probably say that the inflation metrics should go up.

Ofc, focusing on just one thing is very convenient for people who want to tell a particular story. (inflation is so bad! look at housing! there's so much deflation! look at food and TVs!)