Is it acceptable for a referee to reject a paper for superficial reasons? I recently got a short referee’s report on a paper I submitted.
They made superficial remarks concerning notation and writing style, and then admitted that they did not even read the main result.
Is this acceptable for a referee?  

The editor took their recommendation and rejected the paper.
Referees don't reject papers: editors do.  You may feel the report was superficial but apparently the editor does not subscribe to this point of view.

You can make an appeal to the journal or the editor, pointing out politely that since the referee (alledgedly) admits to not having read the body of the paper, you would be grateful if the editor could add some constructive comments so you can make changes and resubmit, but don't hold your hopes up.  

You are unlikely to win by challenging the report directly: if your appeal looks like a complaint it will be ignored; you are more likely to get some traction if you ask for clarifications on why the report was so short, why referee did not bother to read the main body, what specific published work that the referee used to reach her/his conclusion, etc.