I don't think Trump got way with it. He got called out on it, by Coburn as well as by others. If your criteria for "double standard" is lack of perfect uniformity in dealing with mistakes, everybody has a double standard. The fact that Trump didn't make a public apology cuts against him. I don't personally think it's a big cut, but obviously and naturally, people are trying to get alot of mileage out of it.
Trump got away with lying.