It didn't rule that the current administration can't undo the program, it ruled that the administration has to properly justify that decision, and not doing so is unlawful.
At no point did it rule on DACA itself, or prevent the administration from providing actual, motivated and legal reasoning for rescinding the program.
Also
> This was his dissent on DACA.
Which corresponds to the majority ruling on this case, yet I can't help but notice Gorsuch joined the liberal justices in the majority, not Thomas.