I agree, Lindberg did visit Germany several times. But he was "hosted" by Goering et al. and no doubt shown the nice things. It was a recruiting trip.
I suspect some of us here would have admired Germany up to a point, they did some apparently admirable stuff, at first. The downside was of course not publicized.
I give a lot of credit to William Shirer, a reporter over there, who tried to "tell us". He later wrote an excellent book, which is a bit long, but worth reading.