"Only what’s measured is what matters" is much more sweeping than what I've usually heard, which is, "If you can't measure it, you can't manage it."

I understand that managers may conflate the two.

What really sticks in my craw about this mindset is that it's lowest-common denominator management. The spoken implication of metrics-driven management is to keep the organization focused on KPIs, but the unspoken implication is that employees can't be trusted. That is probably true for many employees, but not all. This lack of trust between management and employees is a big red flag for me, bigger than the hassle of micromanagement.