While I don't like that type of rule of thumb, I can clearly feel why it makes sense.
I am on the brink of buying my first home as it is. And having seen peers having earned several hundreds of thousands from their houses over the past 4-5 years really adds pressure and FOMO.
I guess that is the sign to be extra cautious on buying. And I also think that this feeling is quite prevalent creating the perfect storm for a financial crisis.