I know that. That wasn't out of hatred but cause of the issue of durand line.
You can google declassified CIA documents from 1960s, there even was talks between Ayub Khan and Afghan King to form a joint confederations of states. So there is that.
Its a long mix bag of history. In 1980s to early 2000s, Pakistan was very popular in Afghanistan. It changed after we gave NATO the supply route via Karachi Torkham into Afghanistan and airbases like Shamsi, Jacobabad etc.
But I think both sides need to settle issues and they are. In recent trilateral meetings in China, Afghanistan is getting integrated in CPEC and Pakistan and Afghanistan are drafting rail agreements too as we speak. All of that getting implemented is another issue considering the track records.
Most sensible Afghan Pashtuns know it isnt happening. Only if Pakistan alienates its own Pashtuns in some unprecedented way.
Afghanistan isnt Pashtun majority. Pakistan has the largest number of Pashtuns on planet and majority of those wants to do nothing with Afghanistan. The reason Afghans call them "Gul Khans" cause they are patriotic to Pakistan instead of Loy Afghanistan.