In the worksheet of Clippers,
http://www.allaboutcircuits.com/worksheets/clipper.html

Are the outputs of Q8 and Q10 correct?
I feel they should have been reverse of what they are. Any corrections?

 

Nope, the graph is correct.

Remember, you can see the voltage when it is applied across the diode and is blocked by it, not when it is drained through it because of forward biasing.

 

This is somewhat simplified. But then a diode is forward biased. Think about it as a closed ideal switch. Then an ideal switch is closed. It will have zero voltage drop