joseph: Have YOU considered that these gedolim may have not have been at home when neighborhood children came collecting and that is why we don’t know what they did? Were you personally with these gedolim on any halloweeen to know what they did? People who actually spoke to R’ Yaakov or were in Rav Pam’s house saw what they did so stop downplaying their actions so as to conform to your shita.
Based on your shita, one shouldn’t dress up in a costume on Purim because these gedolim didn’t dress up in costumes on Purim.