The passage includes information about risks that eating meat can pose for the health. It also makes note of the concerns surround farming practices. Neither of these are immediate reasons to be concerned about the environment even though the excessive use of fertilizer in farming is indeed very toxic for the environment.
The mention of environmental problems right after that of farming practices confirms that there is a possibility that vegetarianism can help alleviate environmental problems.
I think C cause the act of charity their neighbors showed towards them which differs based on how they might have treated their neighbors as family or like an outsider
