That is the same with most things, we say the verb before the object(s).
I agree that the concepts behind S-expressions are simple and logical, but expressing an entire program using S-expressions is an additional thing that must be learned. Other languages chose a syntax that is closer to what people are used to and that helps with the adoption of the language, even if the language loses other capabilities.
On the other hand, I have taught courses at the high school level at the same school based on "How to Design Programs" [1] using the Racket language. Although I can explain the concept of (+ 6 (* 1 0) (/ -2 2)) rather easily, the students make mistakes writing expressions for several weeks.
Plus when you're used to trees, linearization and parsing, you *fix the way you see fit, pre post or in ...
The syntax referred to is S-expressions. They are a simple and elegant way of writing trees. Lisp was originally supposed to have M-expressions which would be more like mathematical notation, but it was found that Lips users actually liked S-expressions.
The reason becomes obvious after some amount of Lisp exposure. S-expressions are so simple that before long one does not even see them any more. The parentheses give way and one can just look straight at the Lisp code itself. For this reason many Lisp programmers do not even edit the S-expressions. They instead use something like paredit to edit the underlying tree directly.
It's similar to how readers don't really "see" the letters that make up a word in many natural languages. And, further, they don't see the words that make up certain expressions. We have this fantastic ability to internalise language but so many are choosing not to use it when it comes to programming.