Milk ladder - is 1yo too early?

Thinking out loud really. My son was diagnosed with cmpa in the first week of life because he wasn't tolerating milk. As soon as I cut it out he was fine.

We've been weaning fine too, he has a very healthy milk-free diet. I don't feel overly restricted because he enjoys dairy free cheese and milk tends to be added to the processed food.

So why am I being told I need to start the milk ladder soon at 1 year old?

I get that there is protein, fat and calcium in milk, but my son is getting plenty of these nutrients already.

I suppose it would be useful to know if he was allergic or not, but when your child cant speak and you don't know what is truly going on inside, why is there such a rush?

(The milk ladder diagram is also full of processed unhealthy food, what's that about)