Most of the "official" information on protein is that you shouldn't eat very much, because excess protein damages the kidneys, but as you found, that doesn't seem to be the real case - it seems that consuming excess carbs is what actually causes the damage. Then once the damage is done, that's when you need to limit the protein, because the kidneys can't handle much of it at that point.

Using reasonable amounts of protein powder (whether from whey protein, or some other source) shouldn't be a problem as long as your kidneys are still functioning properly. Once some damage is done, that's another story.

But that seems to be the case with so many physical problems - the ridiculous amount of carbs we're being told should be the base of our diet is the primary underlying cause of so many problems, but being consumed in such large quantities, they cause damage to organs and other body parts over time, including those which need to work properly to handle the amounts of proteins and fats we need to stay healthy. Unfortunately, in order to avoid worse problems from the damaged part, that means the default advice is to avoid all but minimal amounts of the macro-nutrient that the damaged organ can no longer handle, which results in an increase in carb consumption, which then damages more organs and systems.