Did you not see what G20 protesters did in Hamburg? They destroyed part of the city. Did you not see what protesters here did to the Plaza del congreso when the Congress was voting controversial legislation? They desyroyed the Plaza. What was Macri suppose to do, wait and let that happen in BA during the G20? Because that show of force was displayed, there weren't major incidents.
The Argentines I know are actually glad that Macri and Bullrich are enforcing laws, such as that you cannot block streets during a protest. When the police act in that kind of situation, they are not been "repressive" as the Kirchneristas will tell you, they are doing their job.
Their has been more violence, but it has in large part been caused by Kirchneristas and far left wingers; they are power hungry and will do anything to return to power. They are the responsible ones.