Consider what Trump did in those few sentences:
1) Made clear that Kemp does not have his support for reopening parts of the state's economy, providing him plausible deniability if things turn bad
2) Said Kemp is free to make his own decisions, even if those decisions are -- in Trump's mind -- very bad and wrong
3) Made sure the people of Georgia know he loves them very much, especially those who use nails salons and tattoo parlors
One plausible theory I heard for Kemp pushing for reopening so early (beyond outright incompetence) was because Georgia Republicans want to minimize the number of out-of-work people that qualify for unemployment. But I have to believe he was expecting a pat on the back from Trump, not the knife he actually got.