All the sources for the saying that I came across contain additional statements which limit to which cases this wisdom can be applied. For example:
Overigens moet je hier wel mee oppassen en zijn er twee verschillende soorten kraken van elkaar te onderscheiden. Lange doffe kraken betekent sterk ijs, maak je geen zorgen. Korte felle kraken en breekgeluiden betekent het ijs is aan het breken, houd snelheid zodat je niet stil komt te staan op het ijs en rijd zo snel mogelijk naar de kant
By the way, you have to be careful with this and two different types of squatting can be distinguished from each other. Long dull crack means strong ice, don't worry. Short fierce cracking and breaking noises means the ice is breaking, keep speed so that you do not come to a standstill on the ice and drive to the side as quickly as possible
Another observation is that weak ice tends to break without a warning, so if you get to hear the cracking without instantly going for a dive, you're likely on safe ice.
Note that serious advice about safety of ice doesn't mention cracking at all, instead relying on actual thickness and visible features (color and transparency).