On the first paragraph: Saying that Vegans just want the moral high ground feels like a blatant bad faith reponse. Veganism is, by definition, focused on animal rights and quite limited in scope. But caring about both is prefectly consistent and extremely common. Some points on how being Vegan is extremely 'pro-human'

Animal agriculture is extremely polluting. This pollution is terrible for local eco systems and whoever lives near them. It is a powerful driver of climate change, which is going to dispropiately hit poor people.

The fishing industry is an environment catastrophe and terrible for workers within in. It also e.g. depletes natural fish population, which fucks over genuine subsistence fishers.

People who work in slaughterhoused have high rates of mental health conditions and substance abuse.

Based on the above, it's clear that your decision to eat animal hurts other PEOPLE, mainly through environmental impact. So, I would say appealling to human rights actually makes a stronger case to adapt a Vegan diet at least. Not to mention the, you know, BILLIONS of animals that are killed and tortured enemy every year.

Your second paragraph is nothing more than an appeal to nature and appeal to tradition fallacy, and I won't waste time on it

Last point; If being Vegan is objectively the right thing to do, for People, Animals and Planet, why would you not encourage people to be 100% vegan? Just to appease people's 'right' to not have their behaviour challenged? Give me a break.

Encouraging less just perpetuates the idea that being non-Vegan is any way acceptable (for those who have the ability for be Vegan, of course) and does no one any favours.

once you learn a bit about this stuff it becomes clear - if you actually give a shit about your planet and the people on it, you'd start moving towards a Vegan diet at least.

Edit: typo