We also know there's a very massive and small something at the center of the Milky Way, because we can see things orbiting it. (See https://en.wikipedia.org/wiki/Sagittarius_A* video "Stars moving around Sagittarius A*, 20-year timelapse, ending in 2018")
I think I may be forgiven for assuming you got "new study" from reading the HN title, and not from dating the 2014 paper relative to your participation in the field.
Dates blur at my age, I opened the linked article, saw Mersini-Houghton, and was happy to run with 'new study' as it was certainly within the last decade .. :)
I'm more numerical engineering | geophysical data aquisition than astro .. although there's overlap as projects such as SKA need a bit of ground signal elimination in their processing pipelines.
In any case, the paper doesn't claim that black holes can't form.
It claims that under conditions X, Y, and Z they don't form.
And, as usual, there's been a slew of robust responses.
[1] http://www.icra.it/MG/
[2] https://www.imperial.ac.uk/people/j.gauntlett