No one called to end anti-monopoly.
Rather a specific anti-monopoly activist, Matt Stoller, was revealed to have played fast and loose with his sources, and to have ignored actual pro-monopoly forces in housing.
Every day, local anti-housing activists lobby local politicians and defend status quo land use rules that grant a de facto floorspace monopoly to incumbent homeowners and landowners. Meanwhile some anti-monopoly activists are incapable of seeing a monopoly or anti-competitive behaviour unless it involves a corporation.