Charles only has two sons. That said both son's children should be princes or princesses. If the Queen did it, for one of Charles's sons she should have done it for the other. I don't care about tradition or rules etc. This is the first biracial child in the family and that is another reason Archie should have HRH and be a prince. It looks as if the Queen favors one grandson's children over the other. And then to be told your baby would not have security. Does any realize how all looks? I see H&M's point.
The problem is that Harry and Meghan seem to have trouble differentiating between the monarchy and private familial relationships. Within the monarchy, there is a hierarchical system - just like in many other places. For instance, the Vice President of the US is not equal to the President. They're just not, and it's the same here.
Harry is not equal to William, Meghan is not equal to Catherine and Archie is not equal to George, Charlotte and Louis (Charlotte is not equal to George either, and even Louis is not equal to Charlotte, "spare" of her generation). They don't have the same positions, and advantages as well as disadvantages of their positions will naturally differ.
Within the monarchy, there are actually two groups of the Queen's great-grandchildren right now.
A: George, Charlotte & Louis
B: Savannah, Isla, Mia, Lena, August & Archie (so it's not like Archie is specifically singled out or disadvantaged in not being made a Prince)
That is the monarchy. In a personal capacity, I am sure that the Queen is a loving great-grandmother to all her great-grandchildren and does not favor one over the other.
There are other biracial children in the BRF, by the way, Lady Davina Windsor's children.