I agree with much of what you said. Particularly after catching some of the author's errors myself while reading this quickly. (I would wag my finger at the author on missing such HUGE errors actually, especially as he may effectively be slandering a man, much less a dead man who can not defend himself.)
Second thing Debra I might contribute is to suggest my uncertainty of your statement, "He obviously had accepted the belief that sexuality was sinful." I would first suggest that this too is presumptious with such little information, and in fact more likely an error based on other articles and documentaries done on this man.
It does appear more likely that this guy would consider sex in marriage, a gift and joy — if practiced within the marital embrace.
(One example better justifying this possibility comes from his roommate in college, his best man at his wedding and his brother in law. Which I believe one might find more credible — and a better source, than someone's speculation. His brother in law's story suggests that Jim's "struggles" ... that the author (here) believes are repressed homosexuality ... may better be explained as his attractions TO women, DESPITE his fight to hold true to his speculative thoughts on true discipleship and marriage ... views he activly propagated to ALL his collegiate peers — to which he "crumbled," asking Elizabeth to marry. (https://urbana.org/article/my-roommate-jim-elliot)