The irony of this strip is that Thanksgiving actually has its roots in Sukkot!
The Puritans, yes, were Christians… but the reason they were called “Puritans” (and discriminated against) was because they wanted to “purify” the faith… they were largely Torah Observant (the biggest difference being some sects kept Shabbat and some kept Sunday), including keeping — as best they knew how — the Levitical Festivals, and eschewing all the so-called “Christian holidays” (i.e., Christmas, Easter, Valentine’s Day, etc.) because they’re of pagan origin.
Shabot didn’t do his research on this one! 😉