Sorry about double post above. Many, many researchers who had no reason to hide their findings or shade the truth, have looked into this matter over the last 70 yrs, and solid evidence is lacking [to say the least] for the essential contention of the article at top of thread. Notice its innuendoes: every man Hitler ever talked to or had as a house guest is used to imply this, and the substantial offsetting evidence which many a researcher has adduced is never even alluded to.
I would rate the acceptance or confidence level of the article at head to about 20% and label it mostly bogus.