there seems to be quite a few learned pilots that disagree with you about the cruise speed issue.
With respect, that doesn't mean they are necessarily correct.
“Even when all the experts agree, they may well be mistaken.” - Bertrand Arthur William Russell
I would also hope that any good instructor pilot (yes even a checkie) would also offer some praise and encouragement when their trainees do something well - it's amazing how well people learn when the atmosphere is good.