Is it permissible for a teacher to eat food provided by people whose livelihood comes from drugs, if invited to do so, and if his non-acceptance might lead to accusations of arrogance?

The Prophet, peace and blessings be upon him, commanded us to accept invitations. So, if these people invite you, accept their invitation with the intention of calling them to Allah Almighty and building bridges of communication, so that you may advise them and clarify to them the prohibition of selling and consuming narcotics. The mixing of their wealth with the unlawful does not prevent you from accepting their invitation and eating from their food, for the Prophet and his companions dealt with disbelievers and Jews and ate from their food.