Earlier quoted context omitted.
Ever killed a fly because it annoyed you? This is not much different. In fact, this was done for science.
I try not to kill flies, no. The only exception is for multiple flies that won't go away. Ditto for ants. It's a bit strange that violence toward insects is fine, but violence towards dogs is not. Ever killed a dog because it annoyed you? That said, doing it for science at least has a justification.
I find it much stranger that violence towards farm animals is ok but not pets.
At least there are principled reasons to care less about insects (much less complex nervous system), I can find no principled reason to care more for dogs than pigs.