Why are spaces not allowed between function names and parentheses?

I’ve recently come to realize when using other languages, that I really like to write a space between a function name and the tuple that defines its input arguments, as in

fn (x) = x

instead of

fn(x) = x

This feels even more relevant, when calling functions in a compound fashion, as in

norm = sqrt ( sum ( vector .^ 2 ) )

as I feel that it makes lines like these much easier to read (for myself). Is there a particular reason why doesn’t Julia allow the use spaces in these places, and instead throws an error

ERROR: syntax: space before "(" not allowed in "fn ("


Check this older thread on the same topic and in particular this post from the boss.