The FBI is correct.
Preppers are dangerous. They have a will to live and to outlive those that wish them harm.
Preppers are people who think about the possibility of civil collapse, no matter the timeframe, and have the peace of mind to gather the materials and stockpile the reserves in case it is required.
Preppers are not impulsive. They are actually the absolute opposite. They are prepping for a disaster they know not when, and slowly they can collect the required equipment and stock to effectively live and outlive and issue that arises.
I was told once that shrews survived the meteor and were one of the only creatures that survived and eventually evolved to create all mammalian animals today. They survived because shrews are damned good at prepping.
Hence, prepping ensures survival.
Preppers are not insane to want to survive.