Irresponsible drivers/pool owners aren't always the cause of the deaths related to those items. If 2 cars crash because one person had a lapse in concentration or something, which is all it takes for an accident to occur, that doesn't make that person an irresponsible driver.
If a kid manages to get into a swimming pool and slips in and drowns, that makes them an irresponsible parents, not an irresponsible pool owner, which is why you can be charged with manslaughter for negligence.
If someone commits a mass shooting or kills someone with a gun, not in self defense, then they are an irresponsible gun owner/crazy/ill whatever you want to call it.
You're thinking too much into the analogies and not the actual issue at hand