The buried lede is:

“Meat likely played a significant role in the expansion of cranial capacity—larger brain development—during human evolution.
…
Lüdecke and her colleagues’ recent work, however, suggests the transition to meat-eating did not happen during the lifetimes of the seven studied Australopithecus individuals
…
“These are still fairly ape-like, small-brained hominins, that already walked upright but had a more ape-like walk,” Lüdecke tells NPR’s Nell Greenfieldboyce. “Here, for the first time, we have actual numbers to put on there to say, ‘Ok, not much meat was consumed for these small-brained hominins.’”

So, yeah. They’ve confirmed that we were still small-brained hominids when we were still mostly vegetarian.