One really has to wonder why - even without the prohibitions of slander - did
Yitzchok feel that it was important to tell this to Esav. If we can discover
that, we may find that that consideration outweighed the prohibitions of
Lashon Horah and Rechilus.
Another Loshon Horah question: The Chofetz Chaim writes that publicly
someone is Avak Loshon Horah because it may lead the listeners to say "Oh
well he also...." Why does almost every Rabbi, relative, or other public
speaker praise the honoree at Brisim, Bar Mitzvahs, fund raising dinners,
I think that we can safely say that the concerns of the Chofetz Chaim are
definitely well founded! We may not all vocalize it, but I believe most of
us think about the praises being bestowed on the fellow, and the reality as
we perceive it!