The way i think about this is that it is an excuse, but it's not an excuse to not try to work around it.
We all do our best, and for some that really isn't a lot and that's FINE! But there are also probably ways you and others can find that enable you to do a whole lot more, which benefits everyone.
As a really really concrete example: I simply do not have the mental energy to constantly take proper care of my teeth, so i don't try to hold myself to that standard since it would eat away at me and make me fucking miserable.
However i also don't just give up, instead i do my best to brush when i have the energy for it, i take flouride pills to strengthen the teeth, i try to avoid sweets and stuff that harms dental health, and i literally just swish some water around my mouth every time i drink (this dislodges the food scraps and adds a little bit more flouride to the teeth).
Yeah it's not as good as properly brushing my teeth regularly with toothpaste, but it's the best way i've found to take care of my teeth while still being mentally sustainable, and that's all you can ask.