I believe you are mistaken based on Mueller's own statements[0]:

    > … Mueller said. "We did not reach a determination as
    > to whether the president committed a crime."
    > 
    > That statement was more in line with his report, and
    > with his earlier opening statement to the Judiciary 
    > Committee, where he said, "Based on Justice Department
    > policy and principles of fairness, we decided we would
    > not make a determination as to whether the President
    > committed a crime. That was our decision then and it
    > remains our decision today."

Any suggestion that the Mueller report asserts that crimes were committed by the president, to my best interpretation, are false. The report does not include any suggestion to indict the president and was never a consideration of the investigation due to the policy you referenced. These claims are repeated incessantly, however, which makes them easy to believe.

0 - https://www.nbcnews.com/politics/donald-trump/did-mueller-me...