Just a reminder that Roosevelt could easily have ordered the death of all Japanese-Americans, and over fifty percent of the country supported wiping out everyone of Japanese blood.
At least Reagan's reaction to such a threat wasn't: "Jail all the gays!!!"
Even accepting your first paragraph as true (doubtful, even with the Korematsu decision there's no way the Supreme Court would've upheld an order for an actual genocide), your logic is as follows:
1-FDR could've done a lot worse than what he actually did.
2-Reagan didn't do the absolute worse possible response he could've given.
3-Therefore, Reagan was not as bad.
Yes, because the Supreme Court would have acted fast enough to stop a military order.
Please, someone read Higgins's post.