This is far from true in my experience. I'm no Lisp hater (I wrote a self-compiling compiler in Scheme) but different syntaxes have dramatically different degrees of familiarity, like Latin letters and Cyrillic. How long do you think it would take you to learn to read phonetically in Cyrillic as fast as you do in the Latin script? It takes the humans months or years, if they ever arrive. But, also, some notations are more usable than others, even for experts, just as with other kinds of user interfaces. Flat is better than nested, simple is better than complex, complex is better than complicated, Perl and MUMPS are unnecessarily error-prone, etc.
I shouldn't have mentioned LISP because I don't use it and I actually find the parentheses to be annoying, but it's a paradigm and you need them. Cyrillic at full speed is obviously weeks. But Erlang is very math-notation-y and when I introduced people to some Erlang code I'd written they understood it once I'd given a presentation on it and were then able to do similar things.