1) part of it is justification, part of it is...who knows? macho posturing? kool aid drinking?
2) shooting dogs is a thing in a lot of these cases. shooting them in front of the kids is a unique twist, though it has happened before.
3) compensation? maybe. but it's a long shot. see balko, radley:
http://www.theagitator.com/category/paramilitary-police-raids/