“Excuse, but don’t we do the same thing every Friday night and on every Yomtov? There is nothing goyish about having a nice meal and giving thanks to Hashem.”
The problem is not the idea of giving thanks to G-d, its all about the timing. Succas is called “Chag Ha’asif” the holiday when we thank G-d for the years crop. We don’t have a reason to do it when the pilgrims did.