They have to do this, because if they don't they could lose their trademark protection. They have to pursue all instances of unauthorized use of trademarks, or they could be told down the road "since XYZ company used the pentastar on their parts and you knew about it and didn't demand they license them and didn't try to stop it you can no longer claim exclusive use of it." That happens so it's not surprising that Chrysler enforces trademark infringement. But sometimes their tactics seem very heavy handed. Maybe those folks deserve it for ignoring previous warnings, I don't know.