Clearly, their reaction was extreme and aggressive (From your link) :
On June 28, 2020, about 500 Black Lives Matter protestors entered Portland Place, a private gated neighborhood, in an attempt to walk to the home of St. Louis mayor Lyda Krewson on an adjacent neighborhood street. The crowd aimed to demonstrate against Mayor Krewson and demand her resignation after she publicly read the names and both partial and full addresses of those who had submitted letters calling to defund the St. Louis Metropolitan Police Department.
Livestreamed video showed the first protesters entering the community by walking through an intact gate that a man was holding open; Twenty seconds later, the video shows Mark McCloskey with a rifle outside his house, yelling at protesters. McCloskey later told media that the protesters "smashed through the historic wrought iron gates of Portland Place, destroying them, rushed towards my home...put us in fear for our lives", and also that "the gate came down and a large crowd of angry, aggressive people poured through. I was terrified that we'd be murdered within seconds". While the gate was damaged at some point in time, it was unclear who had damaged it.
As the crowd approached, McCloskey shouted "private property" and "get out" multiple times at protesters. Protesters marched past his home; others marched closer to his home. Mark and Patricia stood outside their front door with an AR-15 and handgun respectively. Several protesters confronted Mark and Patricia in front of their home, only several yards apart, exchanging heated words. At one point, Patricia walked onto the grass between her home and the sidewalk where protesters were marching by. Some protesters were heard asking others to leave and move on, while other protesters were heard threatening the McCloskeys.
During this time, Mark and Patricia pointed their guns towards the crowd. No shots were fired and there were no injuries. Shortly after the incident, the McCloskeys told reporters that they support the Black Lives Matter movement and civil rights. They later criticized BLM protesters at the 2020 Republican National Convention. (more)