We grow plants to feed the animals we raise for food. This is far less efficient than eating the plants themselves, and it leads to more animals being killed for the reasons you mention.

So we are killing billions of animals each year to eat. I very much doubt we are killing trillions of animals by farming plants. Can you show any sources for your claims.

Also yeah, the fast majority of crops is farmed for animal feed, so your point is even more invalid.