Nothing to do with luck .. all to do with reality.
Yeah, and average house has a bottom sound level of about 32dB. This means for something to be audible it needs to be making more sound pressure than 32dB .. so if your house is 32dB your pumps are louder than 32dB. My home 30dB unless someone is driving by which is rare .. or we have other things besides our computers running which is almost as rare .. so here a pump generating 34dB SPL is audible in room it is in .. you know, like room would sound if there was an aquarium running a pump in it.
I've see others like you claiming their CLCs are silent, until they convert back to air coolers and are amazed at how much quieter their new air cooler is than their CLC was.
Same applies to accurate testing of CLCs' and air coolers'where instead of CLC being mounting as intake and air cooler uses warmer air causing air cooler to have higher CPU temps compared to testing where component air temp is monitor and used to determine delta temps of both air cooler and CLC showing air coolers cool CPU just as well as CLC, and can do it at lower noise levels too.
Important thing is you are happy with your system as it is.