Earlier quoted context omitted.
Of course, because if we make feeding antibiotics to livestock illegal, it can only be enforced by lynch mobs. C'mon. Do you really think every food regulation is being watched by military police who will come and beat you up if you break said regulation?
It's no secret that if you defy the authorities they escalate the amount of coercion they use. You just need to follow the progression far enough to get to the violence. They start with a polite court summons, then send a police officer to your home, and if you don't come quietly they'll physically force you. If you manage to resist that, well now you're resisting arrest so it doesn't even matter what the original su…
Also, in this case, the individual dosing livestock with antibiotics is actually harming society, in which case I think it would be okay to physically detain him/her from doing so, rather than just saying "this is just too much effort, guess we better let him do whatever he wants". In most scenarios though, I don't think this would be necessary.