Highlighting contradictions in people's beliefs is good, actually. If they choose to be willfully ignorant of cruelty while reaping the benefits, then they're not going to face that contradiction from you asking nicely while carefully avoiding any implication that they might be doing something wrong. Rather, it's the opposite - you want to make it as difficult as possible for them to ignore what they're doing. But of course, since they are trying to remain ignorant, it can be expected that they will react with hostility when you call attention to it, no matter how nice and polite you are about it. The only way to avoid provoking such a response is by allowing them to keep the cruelty out of sight and out of mind, in which case they will have little motivation to go vegan and you've rendered yourself useless.

People who have neither been convinced nor convinced others of veganism love to offer their perspective on how we can be more convincing which invariably seems to consist of defanging our criticism and going out of our way to avoid making people to confront the cruel realities caused by their actions.