I've thought about that as well. Is an ethical vegan who has a dog inconsistent in their beliefs? Probably yes if they don't let it have interaction daily, but even if you leave the dog at home for just ten hours while at work I would expect that the dog has a negative experience for that time.

Compared to wild animals that are in pain and hunger most of the time? Nature doesn't optimize for happiness. Unhappy creatures are more likely to seek out the things they need to survive and propogate.

Still, I understand the line of thought. My cat sometimes acts very upset when I'm not giving him enough attention or when I make him get off my lap when he's comfy. I think this is probably just learned behavior (he acts emotionally manipulative because it triggers a reaction from me), but sometimes I worry that because his realm of experience is so limited, that minor inconveniences are literally the worst things he experiences and therefore seem quite terrible to him. I don't really know which is true.

You don't have to be with them all the time, but you do have to give them a lot of attention when you are around.

The trick is to get too many cats, so that they always have each other and are less upset when you aren’t around.

2 is probably enough, but too many is preferred