On VHF static and atmospheric noise is almost nonexistent. It's not the squelch and it's not static you hear; it's random electrical noise (white noise) produced by the receiver itself, turn off the squelch and you'll hear a steady hiss. Due to the nature of AM vs. FM receiver circuitry internally generated noise sounds louder on FM.
For what it's worth, in a receiver signal to noise (S/N) ratio is more important than overall sensitivity so pay attention to published data on "quieting" levels. Just because it's sensitive you still can't hear weak signals through a lot of noise.