I never had a problem with this, and my first few languages were BASIC, assembly and C. LISP came naturally to me a few years later.
I think the problem is that people are /used/ to imperative programs, and aren't given real practice in functional programming.
There are also FP zealots, some of whom maintain that learning IP first causes damage. I think this attitude is toxic and doesn't actually help their "cause" (as if good tools needed a "cause" -- good tools should just be good tools).
That way they get a good notion of what programming actually is.
I'm only now getting into functional programming. I would not have grokked it very well when I was like 12 years old.