It was not quite as damning as people liked to understand it.

Well, that begs the question, "Which people?"

His Wikipedia reference (not always the most reliable, I'll admit) includes the following:-

... he cooperated with the House Un-American Activities Committee (HUAC) and agreed to testify, fearful of losing his source of income. Ives' statement to the HUAC ended his blacklisting, allowing him to continue acting in movies, but it also led to a bitter rift between Ives and many folk singers, including Pete Seeger, who accused Ives of naming names and betraying the cause of cultural and political freedom to save his own career....

I have heard many accounts of this nature from older folk singers, both British and American, dating back long before the internet came into being.