there are various confusing narratives, depending on the account/source one looks to. i think the most reasonable, balanced view based on all these sources is.. that yes, some pashtuns in the lashkar engaged in this. but they were small minority. and the reason was they did not have proper funding/supplies. for them it was a raid, plain and simple. muslim brotherhood with kashmiris was not as important, when ideas of faqir of ipi and anp traitors still held some currency in tribal areas.
that said, the blame falls entirely on whoever was in charge of planning, logistics and promising them more treasure in srinagar. that whole line of thinking is wrong. any force fighting for the cause should have been given adequate supplies. nationalistic fervour among muslims of punjab was very strong, and one could have easily gathered enough money from even poorest villages by invoking Pakistaniyat and kashmir cause.
unfortunately the congressi propaganda was very strong in kashmir valley. they essentially blocked out news of dogra genocide of muslims in jammu, and highlighted baramulla or surrounding areas trying to make it look like kashmir being invaded by foreigners. sheikh abdullah had a big role to play in this, and kashmiris followed what he said. until they realized bania nehru cannot be trusted after he put sk abdullah in jail, rest is history.
it is best to admit we all made mistakes, and did not uphold sacrifice of our martyrs worthily. we could and should have done much more. but most important is to highlight the choice of kashmiris as a fundamental universal human right, through purely political, humanitarian and non violent method. this is only way for plebiscite now.