I’m not sure why we’d consider oils, emulsifiers or fortification and indicator of poor health outcomes.
Whole grain cereals are associated with positive health outcomes so I’m not sure why something being a liquid cereal would be a negative.
FWIW I would agree that oat milk is probably an inferior milk to dairy in most aspects except fibre content, but that’s not because of the reasons you gave. And soy milk seems either equal or superior to dairy milk in all outcomes that I’ve seen.
By whom? Oils are not necessarily bad for you.
And the low fat milk in the carton is pretty far from natural, where oat milk in example seems to be pretty simple process based on quick googling:
https://www.loveandlemons.com/oat-milk/
Of course any industry can make anything ultra processed, like oat milk, but the generalization was wee bit hefty here.