Good observation Doubting Bro. I too was struck by the frequency of his using the phrase "rightly disposed".
At first I thought this is Morris merely projecting his conceit and arrogance as well as his disdain of others whose beliefs are divergent from that of WT teaching.
Whilst I still see the GB as conceited and arrogant, yet his repeated use of "rightly disposed" reminds me of the teaching of an "elect". If memory serves me correctly, I think it's a Calvinist teaching / doctrine.