TD I joined in early 90s. Knew nothing of their past. Went through the Live Forever Book. Some teachings were compelling others bonkers. I questioned the bonkers bit big time. Sister studying with me started to agree with me, next 2 elders arrive on my study. I'm still asking my questions, they effectively lied to me but more in the way of being very clever by fudging things, appearing to answer questions but not doing so. They sought to gain my trust rather than reason with me.
"Look if you find anything better, tell us and we will all come with you." That's what one of these elders said.
I fell for their trick - I did not know any better.
Almost 27 years later I said to this same elder "I am certain that the 3rd year of Jehoiakim's rulership is the 3rd year of Jehoiakim's rulership." Then he said "you are irrational."
So you asked do they "believe people are judged based on their receptivity to a tangled, incoherent doctrinal mess that they can't even explain themselves" - I'd say yes. This elder flapped a magazine at me and told me he believed it was the truth cause the mags were translated into so many languages (not that one word was necessarily true).
You said: "When the basic message presented at their Memorial observance starts to fall apart, then so does their most basic claim about themselves and who they are." I say - yes. They are neither Christians nor Jehovah's Witnesses.