From various accounts I have read, the protester shot and killed in Austin was carrying an AK-47, and he was shot by people with handguns inside a car he approached. There is some dispute as to whether he was pointing the gun at anyone. All the gun carrying is legal in Texas.
Supposedly, people bring their guns to the protests because they think they need them for protection. It may well be the case that the shooters thought they were being threatened. They might not want to have waited for the guy with the AK-47 to point it in their direction.
It is incomprehensible to me how people can think that having more guns out in public makes things safer. It seems very unlikely that the victim wold have been carrying an assault rifle if it was illegal to do so, and perhaps the shooters would not have been carrying either if it were illegal. In any case, it's obvious that carrying an assault rifle did not make things safer for the victim. Just sad. And the danger continues.