The hardening guide says the following about this setting in its coluns:
"Is desired value the default value": NO
"Desired Value" : True
"Change Type" : Add
hardening guide is asking us to set this value 'True' because that is desired value but it's not default. so without these entries (isolation.tools.diskWiper.disable=true & isolation.tools.diskShrink.disable=true) being made, they will be acting as if they were set to 'False'
Please refer following documentation for further clerifications