Anyone can justify their beliefs. And you can find people all over the world who believe different things. Some people think eating animals is ok some think it’s not. Some people think speeding is ok some think it’s not. There are even people who believe the earth is flat.

And just because you disagree with someone’s reasoning that doesn’t make them wrong.

Now you are appealing to the subjectivity of morality. See arugment 14 at 26 min 40 sec in that video to see this covered. This is a complex issue that will be an absolute waste of time for me to try and explain to you, if you refuse to acknowledge a simple logical fallacy like the appeal to tradition, trying to get you to acknowledge the flaw with appealing to subjectivity as a justification would be a joke.

. Murdering humans is generally considered wrong because it’s harms people which harms our species as a whole. Killing animals to then consume them is looked at differently because they aren’t people and eating them helps our species by providing us food among other things.

So you believe the ends justify the means? If i had undeniable scientific proof that killing all jews would help our species as a whole then you would argue that i am justified?

If anything the video made me dislike the vegan ideology even more because I see the beliefs as very twisted and wrong.

This isnt vegan ideology that you are against. This is ethical reasoning. You don't like the way philosophers reason about ethical dilemmas. Vegansim is an ethical dilemma so follows the same format.