Key word offered is "Ownership"
The property of others, including legal items purchased are none of your business,
especially in the privacy of someone's home.
Just because a teenager gets themselves Hypnotized by immersion into violent first person shooter simulator video games, then "graduates" from their at home repetition training program, by using their developed skills in reality at a shopping mall, religious building, or school.... .
...does not mean the STATE has the Right to confiscate the simulator tool, ie; the PlayStation or X-Box or PC game machine, "Loaded" with first person shooter software,
...as that is personal property that could be loaded with other software "blanks" that doesn't "simulate mass shooting training", that allegedly actually trained and inspired the unfortunate actions, by contributing to dementing the teens mind into the bad mental health.
To advocate otherwise is impractical.
And then there's that other pesky Amendment specific to the individual property:
"The Right To Keep & Bare First Person Shooter Video Simulation Games of Mass Shootings SHALL NOT BE INFRINGED"