Allstate Indemnity Auto Insurance Nasty Tirck to Justify Premium Increases Livermore, California

Last year, I caused a 3-mph rear-ender to another car.  Mine had only a few small scratches, not worth repairing.  Other guy had complete bumper replacement for about $750.  He was obviously not injured, but went to his doc once to be checked out, and Allstate paid about $250 for that one visit, with no subsequent medical issues.  Allstate increased my premium by 184% based on a "2-point" claim (property + injury).  There was no medically documented injury, but the game that Allstate uses is to use the Medical Payments part of the policy for "bodily injury" when there is nothing but one medical visit to ensure that there is no actual injury.  Despite my protestations, Allstate won't budge.  I wonder if this is a standard tactic to increase premiums.