What about food on the altars of idols?

God informs the believers to avoid the altars of idols. Therefore, we should never be in proximity to an altar of an idol in order to be able to eat the food at an altar. This is much like the argument for cannibalism, where some people argue that 6:145 doesn’t prohibit cannibalism. Yet, we are prohibited from murder, and secondly, any animal that is killed without the intention of it being food, therefore, would be carrion. So, there is no condition that one can lawfully be a cannibal.