There's nothing strange about this. You're just failing to recognize the obvious.

Would you seriously have the heart to, say, kick, injure, and torture a calf or lamb that you know was heading for slaughter and was going to end up on your plate?

Do you also fail to see why people ban torture despite still permitting killing in circumstances like capital punishment or war or self-defense or whatever? Would you be okay with getting tortured during your life if you were sentenced to death?

Just because society blessed your excuse to kill a living being, that doesn't make it strange or illogical to oppose your cruelty or their torture during their life. I'm not even taking a position here; this is so obviously not hard to comprehend. If you're looking to point out hypocrisy, this is not an example of it.