Because depending on the country, it is indeed true. Not many houses here in germany have an AC installed. Because it was just fine not having one a decade or two ago.

I live in the UK, and seeing air conditioning in a house is maybe like a 5% probability maximum. The story is pretty similar in places on the continent I have seen, except maybe bits of Spain and France. Sure, commercial buildings, trains (with a notable exception being hell the Central Line), and cars have AC, but that's only for when you go out in the day, except for hotels that more often have AC.

I just saw a short on YouTube of some Irish guy talking about how he didn't have or want AC

Not only is AC rare, but new apartments aren't always equipped, and some countries literally forbid AC installations (Switzerland) in the name of energy savings (which means people then buy those terrible mobile units, which are way less efficient)