a vegan diet is the most ethically viable

That in itself is the spirit of the original premise, which is, that ethics and morality are totally subjective to the individual. It is illogical to break history down into progressions of moralistic belief because at the end of the day it comes down to the individual.

Recreational Marijuana should be legalized

Some goods prove to be more harmful to the general-welfare of the public than others.
3 supporter.

Running is better than cycling.

Running is a more natural activity, whereas bicycling is artificial.
2 fallacy report.
Fallacy Of Is To Ought
Appeal To Belief