Is it a sin to eat animals and are people going to hell for it?

It’s not about not going to hell. It’s about doing God’s will. His will was clearly stated in the beginning when he said fruit and vegetation is to be our food (Genesis 1:29). And God’s will does not change (Malachi 3:6, James 1:17). We should be motivated to do God’s will regardless of what may or may not be in it for us. Eating animals is contrary to God’s stated will.