>>93260807Ludo is a spastic manchild, almost definitely born after or was too young to remember the last Mewman-Monster War. If monsters have any opportunity to be educated, it probably wasn't afforded to Ludo, being the runt with many heirs to his clan before him.
Toffee clenching his fist in reaction to the massacre reenactment suggests that it upsets him enough to make his composure slip just that little bit. It's up to the viewers interpretation as to what exactly sets him off. Maybe anger on behalf of his fellow monsters, or more likely in my opinion it's more just his raging hate/revenge boner against the Butterflys, since he sure didn't have a problem getting Ludo's goons killed or using Ludo to establish a power base stealing and processing corn with monster slave labor.
There's even the possibility that Toffee was actually alive at the time of the Great Monster Massacre, but I still don't think they meant that kind of "immortal."