Steenamaroo
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Total noob here (just about) has no idea why or how? Sensitivity is a linear thing. A less sensitive mic may be better for high SPL? but probably does nothing at all about room acoustics. What you described is a shielded/damped mic and that is different?
You're absolutely right. It's a piece of information that often gets half-given.
The less sensitive mics result in less room ambience only because they usually allow you to work closer to them without issues.
The SM7b large body, metal grill and foam (one layer or the other) aren't really relevant. The fact that you can kiss it while you sing without plosives is the key point.