Two Amsterdam tenants had great success in reporting their landlord to the Huurcommissie rent tribunal for charging them exorbitant rent. The Huurcommissie ordered the landlord to lower the rent for a small, leaky, drafty room on Keizersgracht from 1,950 euros to temporarily 95 euros per month. The rent for another room in the same building was lowered from 1,200 euros to temporarily 93 euros.
The argument is: if your rent is that cheap, you probably have a side deal going on (like extra pay or work for housing) to avoid taxes and/or social security contributions.
I’m not saying the present system is great, I’m just explaining it and unfortunately some people indeed try “save” taxes that way.
I’m not sure this is exactly the argument, I understood it as: “You rent out so cheap you don’t want to make a profit, and if you don’t want to make a profit you can’t make deductions in relation to your properties.” Which I don’t find great either.