Why would dark energy be a hack? We know that the universe's expansion is accelerating. Since it's accelerating, and not expanding at a constant rate, that means there has to be something driving that. Dark energy is basically a "placeholder" term to describe the phenomenon.
>But then dark energy does feel like a hack, right? Throwing the whole “dark thing” concept under the bus.
Yes, dark energy really is nothing more than a mathematical hack (at least for now). There's a reason that a certain personality type chooses to go into physics and not marketing, with the result being that the market for physics often leaves something to be desired.
I thought the same when reading the article. Dark matter doesn't just seem solid - it has even has mass :)
Dark energy is a whole different story and seems more like the epicycles of the heliocentric model: Adding a mathematical hack in order to fit the model into the data.
I'm remain curios about stationary universe model proposed by Peter Ostermann [1] which can explain the SNe-Ia data with homogeneously distributed dark matter and without a need for dark energy. Also, it is a lot more elegant and "Einsteinian" than the concordance model.