Saw this last shabbos:
Eisov is compared to a pig as it is said... When the pig lies down it stretches out its hooves as if to say, "See, I am a clean animal." So, too, those who rob and extort yet make pretensions of being honorable.
Rashi doesn't spell it out, but it seems obvious to me that he's speaking of Christians, Esav's presumed descendants. This short comment, therefore, tells us something about how Christians behaved in Rashi's time, and also what Rashi thought of it.