How do you keep veganism from becoming an idol?

By learning the connection between veganism and God’s ideal of stewardship (Genesis 1:28-29), you come to realize the two are in harmony (Luke 6:36) and you see that it is God that gives you a heart for animals (Psalm 145:8-9). Doing God’s will is not idolatry, so as long as you do it from faith and love (1 Corinthians 16:14), you do it to God’s glory (1 Corinthians 10:31). Animal cruelty is much closer to idolatry than veganism because you are placing something else (e.g. appetite, tradition, cultural norms, etc) above God’s will for us to be good stewards over all his creatures (Genesis 1:28-29, Luke 12:42-44).