I think the Fool gets unfairly blamed for certain things that happen to Fitz and the whole Regal episode is def one of them. That was Farseer family drama; Regal wanted Fitz dead from day one and seized his first opportunity once Shrewd was gone and Verity Skill commanded Fitz to find him while the Fool still thought he was dead. A lot of the worst things Fitz goes through are due to the circumstances of his birth and his complicated relationship with his family (the Fool even tells him that the original timeline involved Shrewd having him quietly poisoned as soon as he was revealed.)

I get why people blame him though; the Fool is extremely insecure and afraid that he’s a detriment to Fitz so he’s constantly implying everything bad that happens is his fault. He later admits to Bee though that the main reason he feels so that way is because he worked to keep Fitz alive through some difficult times instead of letting him die peacefully at a young age (which is pretty dysfunctional thinking, but like Fitz, he has issues.)