It's very simple. Using this document, you might interpret Flynn's psych degree as a "common warning sign" and so, as the document suggests, "be alert". A cursory search of Flynn's work, as you show, would alleviate those concerns immediately. The document doesn't claim to be a blacklist and doesn't read that way.

Furthermore, "Engage with other scholars" certainly does includes publishing in peer-reviewed journals; why wouldn't it? And beyond that, some of those publications are co-authored.