Is leaving dogs outside all day cruelty when they want to be inside?

So my dad and his wife have two labs which they leave outside during the day while they are at work. I live somewhere else so I only see the dogs about a couple times a month. Every time I go over there, I let them in because they want to be inside. One of them hates being left alone outside! He likes it outside, only when people are with him. He sleeps all day and prefers to do that in an air conditioned house and on the couch. I know this cause the only time I can get him outside is if I drag him or stay out there with him but as soon as I come in he pushes me out of the way to make sure I don't leave him out. It doesn't matter the weather, he always wants to be inside during the day. Sometimes after them being inside for 8 hours, I come home and feed them and he wont go outside! He'd rather hold it all day inside than be out. The other dog doesn't really care as long as she is with him and not alone. They do have water (though most of the time it doesn't look very clean) and beds in the shade. I don't even think my dads wife has even washed their dog bowls with soap. It's disgusting. One time their bowl had a little bit of non clean water from the day before and my dad went to pour it out and his wife actually told him not too and to just fill it. Wtf? The only times they get washed and get clean water is when I do it. Which isn't much since I'm not over there that often. Whenever I tell them it's too hot outside/too cold out or to just leave them inside because they want to be in I always get the same response "they're dogs, they like it outside". I just don't really see the point in leaving them out, they never go to the bathroom in the house, they don't make a mess, all they do is lay on the couch. My dad's family is just obsessed with the dogs not being inside. They don't like dogs which is the reason. Every time I'm home alone and someone shows up the first thing they say is "why are the dogs inside" It just makes no sense to me. Like it's okay to them if they are inside from 8pm to 8 am but 8am to 8 pm they just have to be outside! I don't get it... I consider what they are doing cruelty, leaving the dogs outside when its 30-90 degrees out. I just don't see the harm in leaving them in. Am I wrong?