As far as the prejudice against certain legitimate backgrounds like acting goes, one of America's best Governors and Presidents was a former actor, so that prejudice is obviously flawed IMO. It's not the background, it's the man.
Sorry.
I know too much about Truman to ever consider him even remotely “respectable”.
He was himself a veteran of our armed forces in time of war.
His treatment of some of those who served under him as Commander In Chief was execrable.