I never understood why people drew such a hard line between protein powder and "whole" or solid food. I can think of many comparisons where a whey protein would beat out a "solid food," not just due to the amino ratios but the other nutrients and bodily mechanisms it supports. Even processing can sometimes improve a food protein, like cooking eggs vs eating them raw. Even some other foods, like vegetables or fruits, can sometimes become more nutritious and more digestible after processed, heated, put into cans, whatever.
Whey = food. It's not just a source of aminos but can affect immunity, helping increase antioxidant enzymes, protect organs, increase protein synthesis more acutely compared to some solids, and a bunch of other stuff.
Some do have an allergy, not just to lactose, but to specific whey fractions.
I'm partial to the more unprocessed source of whey, milk! Lol, mostly because I love the taste. I think milk is like 70% casein and 30% whey?