If you bang your knee every day, you might be so used to the pain eventually that it's like you don't feel it anymore.
Physically if you don't know what it feels like to not consume a damaging and inflammatory diet, it's easy to mistake feeling like shit all the time with normalcy. But it's not normal, it's killing you.
And emotionally if you only know what it's like to do something that causes so much trauma and suffering (both to the animals, and the people who do the slaughtering), you might be so used to a background noise of guilt that you're not even aware that you're carrying it. The only way to know the difference is to change and watch what happens in your mind when you stop running away from the violence you're complicit in.
https://m.youtube.com/watch?v=zqyGkvdvvuE