Typically prosecutors either charge someone or they fail to do so and say nothing more.
Mueller could have concluded Trump committed crimes and said so. He did not do so because it believed it would be unfair to Trump because Trump couldn't challenge that conclusion in court.
If he said nothing more, it would have given Congress and the public the false impression that he had insufficient evidence to prove guilt.
To try to be fair, Mueller said that while he refused to say whether he concluded Trump committed crimes, he didn't exonerate him.
But in context, Mueller restrained himself from saying Trump committed crimes.
Ratcliffe's argument obscures that underlying context, which is important.