Because 13+ years ago Hive did not have the
automatic icon borderizerand and I made these icons 'by hand' so to say. The person that asked me to make the models and icons only needed BTN and PAS icons.
On a personal note I don't find having an icon in all variations (especially those UI ones) very useful.
I hope you understand now and
don't set your rating and assessment of my work on something you don't know or understand.