There are various reasons, but the prime reason is that the Bible condemns both practices. ​ — wp18.2, pp. 4 - 5. How should we view accepting an invitation to a meal?
إِذَا قَبِلْنَا دَعْوَةً ،‏ يَجِبُ أَنْ نَلْتَزِمَ بِكَلِمَتِنَا إِذَا أَمْكَنَ .‏