I would like to offer a counter-argument.

Art is personal, and so is all form of artistic expression. Sometimes artistic expression resonates with people. Art also crosses forms (i.e., animation is art, as is painting, and anime is an overlap). If a form of artistic expression (which, in this case, is Kaur's poetry and how she visually presents it) resonates with a significant number of people, then is not criticism of that artistic expression a mere criticism of it because it does not follow a technical and intellectual standard that we ourselves have set for us? If 4.4 million people found resonance with her artistic expression in such a short window of time (admittedly, aided by the access that internet offers), then could it not be argued that she is a more relatable poet than Maya Angelou? Eminem's lyrics are a form of artistic expression, but so are [insert name of any of the new 'rappers' who just repeat the same word a.i.], but Eminem aligns himself with a school of writing that has set itself loose (or strict, depending on how you look at it) criteria. Who are you, or who am I, to say that Rupi Kaur is a bad artist?

(Disclaimer: I hate her work and I think it's a bane upon humanity what she does; but I also know I'm wrong and that I feel that way because she doesn't follow form or structure of what I think poetry should be).