And it has nothing to do with having no regard for each other.
It has everything to do with it because that is the very thing that started this chain of comments. The user was saying that she likes how when she is single, she doesn't have to take anyone else into account while in a relationship, she shows regard for her partner. The other examples you give are from other chains of comments but I'll still get to them.
I guess I'm just lucky?
If everything always lines up and you can both always do the exact same thing you'd be doing if you were single, yes, you are lucky. Sincerely, good for you.
But that doesn't make other relationship unhealthy or bizarre or OMG what kind of relationship is that?
When we moved into our current apartment, it was closer to my job but not as close as it would have been if I was single because that location would have been too far from my SO's job. And likewise, it is farther from my SO's job than he would be if he were single. Our jobs were far apart so we were limited to a few locations that were OK for both of us because we are weird and it makes us happier to be together than to be in the most convenient location.
I am taking salsa classes and Monday would worked best for me but it is too late for my SO. Thursday would be best for my SO but it conflicts with my yoga class. I guess a healthy couple would just go separately but we go together on Fridays. Saddest thing is: we are actually happy about it.
And yeah, if I come back from having drinks out at two in the morning, I will have to be super careful about noise when cooking (and maybe I'll just eat something that doesn't require much pots and pans) and put headphones in for the movie because our bedroom is between the kitchen and living room and my SO gets up before 5. And clearly that is just completely bizarre to you but to me it is worth it because I get to snuggle him when I go to bed and he mutters he loves me in his sleep and he will be careful about noise in the morning (because our bizarreness is reciprocal).
He also doesn't like sleeping alone all the time and me going to bed when he gets up so I wouldn't do it every night. Because we are unhealthy.
And on date nights, I like to be pretty for him so I make my skin smooth and soft, I leave the comfy sweatpants in my closet and maybe I wear his favorite dress or my hair the way he likes. And maybe that is unhealthy in your book and I certainly know he doesn't love me less on the days I am unshaved and unshowered but I enjoy that we try to look our best for each other sometimes.
I'd like to conclude that I am sorry if the fact that my relationship requires give-and-take and compromises that we are happy to make for each other makes you sad but I would be lying.
we are 100% committed to each other
Well we have a different definition of commitment. Because to me "I do what I want when I want the same way I would if I was single and we happen to always line up through sheer luck" is not commitment. It is luck. "We will make it work" is commitment (and of course, we do this because it is worth it and most of the time, it does line up luckily).
To me, in my first example of having jobs in different part of the city, you either have to pick commitment or the location you'd have if you were single.
**TL;DR: IMO it goes like this:
Healthy committed relationship: balance between my needs, desires and preferences and those of my SO
Unhealthy relationship: lack of balance between the two partners needs...
Singlehood: no need to balance anything. Can care only for me, myself and I.**