It's not disqualified for not being simple, it's disqualified for not making testable predictions. Given two theories, neither of which make testable predictions, the simpler one (and the one that has been studied more thoroughly) is the more reliable.

Otherwise, why not just say that the missing mass is unicorns? And the energy driving the accelerated expansion of the universe is the energy of their love? There's no shortage of radical explanations for dark mass/energy. The scientific community takes them seriously to the extent that they are compatible with past observations and make testable hypotheses that distinguish them from other theories.

> odd to me to see her saying that the new theory is disqualified for not being as simple

No. Her main argument is, the way I read her article, is:

"Farnes in his paper instead wants negative gravitational masses to mutually repel each other. But general relativity won’t let you do this. "

The way I understand it, the author of the paper fails to be compatible with the theory that was confirmed time and again during the last 100 years. She just avoided to formulate that so bluntly.