There are about 250 million dairy cows in the world.
About 75 BILLION animals are killed for meat each year.
Factory farmed dairy is horrifically cruel but it's actually a complete and total lie to pretend that this is exactly what happens to family cows or to cows who are worshipped in India.
Killing is always cruel unless its for mercy. Even "humane" forms for slaughter and religious forms of slaughter are scary and painful for the individual animal.
Meat is much crueler than dairy overall. It's also the most sadistic form of consumption. Because babies drink milk, it's psychologically in the realm of compassion to imagine benevolent dairy (even if that's not the true case). On the other hand, anyone who believes in benevolent meat is a complete wack job.
I think people argue that dairy is crueler based on the abject dairy horrors in factory farming, personal bias to persuade people not to be vegetarian instead of vegan, and/or lactose intolerance/dislike of dairy.