As I understand it most things like stocks with be under the capital growth scheme, taxed yearly, but they left a carve out for real-estate where it only is levied at sale/realization time.
Regardless, I assume the logic behind this exception is that while you can easily sell a portion of your holdings of publicly traded stocks to cover your annual tax burden, you can't sell a portion of a house. You could of course finance, but that's going to disproportionately benefit lenders.
But in the Netherlands, the overall home ownership rate is still about 70 percent (https://ec.europa.eu/eurostat/databrowser/view/ilc_lvho02__c... might need to drill down a little).
In the US it's 65 percent.
Carve outs for home owners are some of the most understandable political strategies across the developed world.
Box 3 on real estate only come in play for home 2+, and rental properties.