This is very interesting...
I honestly do not know one way or the other.
I just have come to trust Drs. Foster and Smith website and Live Aquaria - and it would be surprising to see that they are wrong...?
Also, why do ich infected fish present themselves to cleaner wrasses and cleaner shrimp to be "cleaned" - when if the same fish have no signs of ich they do not?
It is a sales website so they will put a positive spin on almost everything they sell. As for them being wrong - they are wrong all the time, it's not even funny anymore.
As for the fish going to the cleaners - the fish just feel the itching, but have no idea what causes it. Going to a cleaner shrimp or wrasse is a reaction to that itch, and not an indication that the cleaner actually will be able to eliminate the root cause of that itch.
As for the notion that Cryptocaryon may only be present in the gills of a fish, but not on the skin - there are actually contradicting findings to this. Burgess found that if a fish has a Cryptocaryon infection, the parasites are equally likely to be found on its entire body. There is no preference for gills or fin edges. This applies specifically to partially immune fish.
The issue is that single or a low number of nodules are easily overlooked on an otherwise healthy locking and behaving fish.
As for higher temperatures - all that raising the temperature may do is moving the peak of excystment towards the shorter time. It may do the same to the feeding parasites on the fish and move the peak of ripening towards the shorter period of the lifecycle.
However, raising the temperature will not change the established minimum times for the parasite on the fish or in the cyst, and therefore does not shorten the lifecycle of the parasite. Also, shortening the lifecycle is the last you want to do as every following wave will be about 200 to 300 time stronger than the previous.
Add to that the oxygen reduction and raising the temperature is just a way to kill your fish faster.