The frog story is an effective anecdote because even if it isn't true it is extremely plausible. The whipping story is casually racist and by advocating for the most extreme and unbelievable end of a spectrum of possible iterations of an idea it serves rather to discredit it rather than promoting it by inspiring disgust and disbelief.

When I read about the frog I suspend scientific analysis of the frog long enough to get the anecdote. When I read the whipping story I think wow British people are so racist, so disconnected from reality, and so stupid they believe that the people they subjugated in their land are such natural slaves that when not crushed under a British heel they pay to be likewise abused in their own lands.

If you wanted to simultaneously smear the modern Brit and the modern American you could do no better than to let Michael Munger talk.