Why do those who eat beef criticize whaling?

I would like to introduce the debate on whaling when I was a visiting researcher in USA in 1992.
I usually introduced an episode of "The wolf and the dog in the fables of Aesop":
A Dog offered to help a Wolf get regular feed from his Master. The Wolf saw a bald spot on Dog’s neck where the collar sat. Goodbye said Wolf. Better starve free than be a fat slave.
Eating livestock is a double sin. Those who eat beef rob the cow's freedom and kill. In my experience, nobody refuted me. But... 1 decade later, I knew that many non-Japanese students in ecology became vegetarians. I respect that they deeply seek self-consistency. But I do not agree with them if they forced others to adopt their new rules.