Batch Keyword Delete

If you wish to remove all keywords from all selected images, you could use a script:

//forums.adobe.com/thread/290238
//forums.adobe.com/message/1115698#1115698
#target bridge
clearSubKey = {};// create an object
clearSubKey.execute = function(){// create a method for that object
  var sels = app.document.selections;// store the array of selected files
  for (var i = 0; i < sels.length; i++){//loop though that array
    var md = sels[i].synchronousMetadata;// get the metadata for the file
     md.namespace = "http://ns.adobe.com/photoshop/1.0/";// set the namespace
     md.Keywords = "";//set the porperty
  }
}
// this script only works in bridge
if (BridgeTalk.appName == "bridge"){
  //creage the munuItem
  var menu = MenuElement.create( "command", "Clear Subject Keywords Metadata", "at the end of Tools");
  menu.onSelect = clearSubKey.execute;
}

This modified version of the previous script will also remove all Adobe Lightroom hierarchicalSubject keywords:

//forums.adobe.com/thread/290238
//forums.adobe.com/message/1115698#1115698
#target bridge
clearLHS = {};// create an object
clearLHS.execute = function(){// create a method for that object
  var sels = app.document.selections;// store the array of selected files
  for (var i = 0; i < sels.length; i++){//loop though that array
    var md = sels[i].synchronousMetadata;// get the metadata for the file
     md.namespace = "http://ns.adobe.com/lightroom/1.0/","hierarchicalSubject";// set the namespace
     md.hierarchicalSubject = "";//set the porperty
  }
}
// this script only works in bridge
if (BridgeTalk.appName == "bridge"){
  //creage the munuItem
  var menu = MenuElement.create( "command", "Clear Lr hierarchicalSubject Keywords Metadata", "at the end of Tools");
  menu.onSelect = clearLHS.execute;
}

P.S. I have not combined the two scripts into one, which would be the next logical step (editing the code to combine the two scripts is proving to be harder than expected)...

https://prepression.blogspot.com/2017/11/downloading-and-installing-adobe-scripts.html

Select all and use the Keyword panel to uncheck the keywords you want removed.