This is a bad faith argument, similar to saying “so you’ve never left a light on all day?” To someone protesting climate change.
The point of veganism (besides the environmental side) is that there is far too much unnecessary suffering caused to animals; complex and intelligent animals, because of the meat industry. Of course humans will probably always cause death and suffering to animals and even other humans, but accepting this and taking it as a reason for “why should I care at all then” is ridiculous.