How to read a partisan or unreliable historian

Is there value in historians who are openly biased and rely mainly on secondary sources?

Yes, as prompts for further research, but their claims should be independently verified rather than used as a foundation.

An emotional reaction can identify a claim worth investigating, but it does not provide a reliable scholarly foundation. Some books provoke indignation or simply sound wrong, and their value may lie in sending the reader toward other evidence. A doctorate or professional title does not make every statement dependable. The practical rule is to trust provisionally and verify the claims before building further work on them.