https://ask.usda.gov/s/article/Is-butter-safe-at-room-temperature

Meh.

I’ve been leaving butter on the shelf for many, many years. And my mom before me and her mom before her. No issues.

We don’t leave it uncovered.

The longest a stick has sat in my house is probably a month. No noticeable issues.

Maybe 2 months is where it turns rancid, I’ve never got there. But my point is that a blanket statement that butter left at room temp is unsafe is I am quite sure incorrect. Certainly it can’t be left out indefinitely, but it can be left out for weeks at a time with no ill effect.