The main "claim" here is that "Taylor Swift is a bad musical artist."
The immediate problem here is that a claim should assert a statement as fact or true. The topic in the "claim" is a subject that can never be definitively established as such or the opposite.
The article from Medium, written by Curtis Stone, summarizes a compilation of pseudo-arguments in the author's attempt to "prove" Taylor Swift is, by a definition that is not fixed, a bad artist. Many of these use concepts and metrics presented in the form of statistical evidence, but the figures shown are related to the topics on which Taylor Swift bases her lyricism and specific words that may be commonplace throughout her songs.
None of these are evidential, impartial, or definitive metrics by which to measure how "good" or "bad" an artist Swift may be.
The author also does not make a claim that is specific enough to assert a fact. Are they claiming that Taylor Swift is an unsuccessful artist? That Swift does not excel in popularity metrics? Or that Swift fails to make music that would be agreeably placed in the genre(s) she promotes that she makes? Which part of her music career, if not all, constitutes a conclusion that would be based on non-circumstantial, measurable, and fairly collected evidence? Because these questions must be asked, the author fails to adequately define "bad artist" to make an argument for their claim that Taylor Swift falls under this definition.
If an artist's being good or bad is measured by the mass appreciation of their creative works, then Swift currently stands to be one of the best artists of our time. Of course, that's a subjective statement, and it is not agreeable to everybody, nor shall it ever be.
Swift can continue to gain a larger and larger following just as easily as she can lose them en masse. A person's evaluation of the compatibility between her music and their tastes is not related to such.
TL;DR: This can be neither true nor false as the claim does not have a fact to assert. It is an article composed entirely of opinionated statements and circumstantial arguments. The author fails to define what composes a "bad artist," and with no definition, fails to apply the argument that Taylor Swift meets this criterion -- simply because such criteria are impossible for it to exist impartially and as a fact. The evaluation of whether or not Swift's music is appreciated or disliked is up to the person who listens to it, not a statement of fact that can be applied to the masses.