Eating animals isn't the problem. The problem is industrial farming. We shouldn't be eating this much meat every single day and as a consequence we have to treat the animals like prisoners and maximize their suffering. 200 years ago there wasn't a huge ethical problem, because back then the animals had more uses than just eating them. They pulled the plow, carried the harvest, etc so there was a reason to treat them well and keep them healthy. Nowadays we don't give a shit.