... Posting it is to inform us of their warped evil views not an endorsement ...Your alibi contradicts itself. Accepting a link between these groups or belief systems--as you claim--means accepting the author's claims on their face. Which means you accept his claims on their face.
and to deny that there was a link is to believe a lie.
To educate yourself and to attempt to educate others is always an effort to be praised. Education on topics such as this will never make one comfortable.
On this topic, comfort comes only by hiding and pretending to believe a fable. Personally, I'd prefer to know what the enemy believes and what the small facts are which those beliefs are based on.