That may be so, but the article is about cosmologists' efforts to unify so-called 'dark matter' and 'dark energy' into a single something.
"Mass-energy equivalence states that mass is concentrated energy. In his theory of special relativity Einstein formulated the equation E=mc^2. There is a tremendous amount of energy in mass. A 20g marble contains as much energy as a 500 kiloton hydrogen bomb, but this energy is very difficult to release. It can be released through matter-antimatter annihilation, when matter and antimatter come together. Nuclear reactions can be understood to release so much more energy than chemical reactions because of the mass changes."
https://www.brightstorm.com/science/physics/nuclear-physics/mass-energy-equivalence/
Modern cosmology went off the rails when it abandoned classical physics, in favor of pure mathematics. Their current working models of the universe are a dismal failure, as they do not predict or adequately explain observed phenomena.
When the models fail, they don't apply the scientific method to discover why. They merely invent ever weirder goblins to patch over the shortcomings of their basic theories.
The theory simply CAN'T be wrong, so reality must be something different than what we plainly see.