Since when does it have to be politically motivated to be terrorism? Holding people hostage for any reason "is" terrorism!
PREFACE: I am NOT seeking a fight. I think the best response to these crimes is a double-tap from a Navy SEAL, center-of mass/forehead because the nature of the offense is beyond the capabilities of conventional law enforcement agencies.
However...
...these are crimes for profit.
While terrorist groups often kidnap people for ransom most genuine terrorist kidnappings either seek to finance operations to force political outcomes or seek to force political outcomes directing through extortion over the safety of the hostages.
Terrorism, but its very defintion seeks to use terror. But terror is a tool to seek political objectives. These pirates don't seem to care much for Marx vs Mises they just want money. It is the distinction that makes all the difference. Remember, terrorists also rob banks to support their goals and in the process they cause much fear and panic, but not every bank robber is a terrorist regardless of the emotional content of his crime nor should they be treated as such.
Of course, history has a solid precedent that the key to dealing with these jackholes is military in nature because domestic civilian law and its enforcement agencies lack the legislative and enforcement powers to adequately pursue the offenders.