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.