Was it a one-time sudden realization, a nagging feeling you couldn't get rid of, or a back-and-forth process?
For me, it was 5 or so years of back-and-forth waffling between vegan and "reducitarian/VAH" before a very strong dose of magic mushrooms a few years ago gave me a stern kick in the ass about my own ethics and hypocrisy, which is how I finally stayed vegan. The same trip was the beginning of my political radicalization left as well.
That's actually harder than you'd think. It's been like five years ago, so it's basically from the time when people thought rage comics were the hight of comedy. The sub's content changed with the time and all the "most upvoted of all time" stuff is from this year.
Look up "vegan sidekick", it was all the rage on the sub at the time. It might look cringe now but it fed me a constant stream of arguments and counterarguments in a form of badly drawn comics and probably worked better than telling me to read articles or to watch Earthlings would.