It is never clear to me and I'm a native English guy. I often rotate images in the wrong direction because left or right is not how I think when performing a rotation. I don't see the relevance of people who's native language is not english, MC is a multi language application.
Do you turn a tap left or right to turn it on or off? Does your watch turn right? How about water down a plughole?
Windows uses the terminology clockwise/counter clockwise, as does Photoshop and most other drawing packages I've used.
Also what happens if you ask a girl to turn left at a set of lights?
If a girl asks your to turn right when reading a map which direction should you turn?
Are we saying MC should only be used by the male population?