Rocking is only a behavior, one that is common to a lot of unrelated disorders, and one that is also perfectly normal.
If you saw a teenaged girl rocking back and forth, would you automatically assume that she was autistic? Would it ever occur to you that she might be having menstrual cramps?
Or would you instead come to the conclusion that autism and menstruation are related conditions?
... amateurs ...
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The mere fact that science may not yet adequately explain an object, event, or experience does not mean the immediate explanation should automatically default to a conspiratorial, extraterrestrial, paranormal, or supernatural cause.