Why I am not a vegan

[Account1]

Morals serve a purpose. Without morals, it would still be legal to have blacks as slaves.

You are confusing morals that you approve of with morals as a whole. Slavery was introduced in the west under a different ethical standard, not lacking a sense of ethics altogether.
Of course, it is up to the individual to discern what is an acceptable standard of morality and what they consider moral themselves.

But claiming that one's own morals are superior than others is always worth raising an eyebrow for.