If you were to describe Guy Fawkes as the person behind the parliament massacre, would you be being imprecise, or would you be lying?
These guys were linked to killing Americans, were convicted of plotting to kill more Americans, and had discussed the possibility, on tape, of killing an awful lot of Americans in America.
One of the problems with the whole dialog is it becomes a question of whether someone did or did not make up something, and she skates on the real point of what was said. There are terrorists in America. We know that. Does it make their policy a good idea? When a couple of terrorists were caught in America, President Obama made temporary changes in immigration policy. Does that make Trump's policies a good idea. Instead, people say, "She made up stuff about a massacre in Bowling Green!"
Well, how does that play. Within the echo chamber, it plays great. Yeah! Yeah! She's a witch! Burn her! Among die-hard Trump supporters (or at least Democrat haters) nothing would matter. But now, how about those "swing voters" whose opinion actually matters and? It starts with Conway saying "Bowling Green Massacre." Then, a bunch of Trump haters say, "Ha. Ha. She's stupid. There was no massacre." Then, a bunch of swing voters say, "Wait a minute...you can't just make up a massacre and pretend there was one.", and they end up reading an article that says that there was no massacre, but there were two guys who killed a few people and hadn't made up their minds about who else to kill.
When those people start reading headlines, they might be inclined to forgive Conway some exaggeration, because it seems like the other side is saying it wasn't really important because they didn't succeed in killing enough people for it to be a "massacre", and besides, the Americans they killed weren't even in America at the time.