There's also a lag associated with fertility rate decreases. Even if the children-per-woman rate has decreased sharply, the population can still be increasing

There's also a lag associated with fertility rate decreases. Even if the children-per-woman rate has decreased sharply, the population can still be increasing for decades afterwards, because there are still a sharply higher absolute number of women in the relatively-lower-rate birthing generation, thanks to the rate having been higher in the past when they were born. Not caring about lower fertility rates because you don't realize that there's a temporary lag keeping the population increase high seems very careless.