I think the (alleged) double standard is due to the different personalities involved when a crisis arrives. His critics have to face the fact that Trump is not the FDR fireside chat during the depression type, nor does he have Churchill’s “we will never surrender” rhetoric. And of course, while Truman’s approach was: “The buck stops here”; Trump’s is “I take no responsibility.” Still, he can do much good, especially if he lets people like Fauci do the talking.
As to Obama, having a winning personality works. Obama screws up, insults a cop, and apologizes, inviting both white cop and black scholar for a beer. Trump is accused of rape: “She’s not my type.” That’s how Trump rolls, and, who knew?, people get offended. Add to that his insults to half the population, and you can see why people don’t cut Donald much slack.