It looks like a predictable 'rhetort' to Kroll's previous hyperbolic designation of Black Lives Matter as a terrorist movement, with the comment likely stemming on
this and
this incident involving Kroll, notwithstanding his checkered MPD history mentioned further down in the first link.
It also looks like a smart play for him to secure the slot in that district.
The way you preface the term suggests that the confidentiality of the information factors in to whether it qualifies as 'doxxed'. If we accept that premise, then the fact that the protesters knew where to go doesn't conclude anything about how the information got out. There are a number of legal and socially acceptable ways for people to come upon a peace officer's home address without putting in any work engaging in Internet database searches or cracks.All costing valuable manpower, resources, time, and tax dollars to accomplish.
It seems they saved a lot more in each of those areas just by dispatching officers just to monitor the protest and keep the peace.