Tldr mostly for my fellow animals, and because I can.
From the first moment I heard about it, veganism always seemed like the more ethically "evolved" position. Like blatantly so.
Not that I'm claiming to be more evolved lol, but it's a relief to have my behavior more in line with what I know to be true.
I'm primarily against "factory farming" which I view as a moral crime on an unfathomable scale. So for years I just bought local from farmers I knew etc.
But then the more I learned about small scale farming and the more animal farms I actually saw (lots of local farms in my area) the more I wondered if any of it was defensible.
Then I realised I could just not partake in any of it and nothing bad would happen to me. Felt off for maybe a week max, but then totally fine.
Once I knew that, I couldn't go back. Partaking in animal farming became a conscious and active decision that I had to choose to pay into, or just as easily, not.