ive heard that theory before and lots like it.
im not sure if i fully believe it but christians and jews have been doing that kind of thing for millenia.
trying to asign symbolic meaning to parts of jewish "history".
paul did it to the crossing of the red sea saying the israelites were baptised when they were crossing the red sea but i always thought that was clumsy because the water never actually touched the israelites and theres got to be water touching you if youre being baptised.
the theory u linked is very interested and could possibly be true