I often buy books written by shitheads when I end up studying fascism or other radical right wing movements. Heck, even more mainstream conservative movements with radical imagery or frequent dogwhistles. Reading books by shitty people on shitty topics is very important on understanding how the movements work and think.

Reading about fascism from antifascists is good and all, but understanding fascist movements when they are most active requires reading fascist works. Heck, even with books like Mien Kampf, a book with a ton of analysis done by antifascists could still be a potentially useful read for antifascists.