Psychiatry competes with Scientology for patient dollars, so naturally Scientology is against it. The viciousness with which Scientology tries to plow under its competition is notable however. Sci routinely blackmails members it wants to hang onto (i.e. those who can act as salespeople, such as celebrities, and those who still have significant assets or earning capacity for Scientology to loot). It's doubtful that Cruise really believes all this garbage he's spouting. More likely he got in too deep to get out, and so doesn't have any choice but to follow orders.
You know the high-ups in the "Church" have all the goods on Tom, and would spill the beans if he ever wanted to leave.
"Psychiatry competes with Scientology for patient dollars"
Well, that and L. Ron Hubbard was a diagnosed physcophrenic(sp? -- crazy); got kicked out of the Navy for having a fight with a phantom submarine; and, according to his public autopsy, died with injectible anti-physchotic drugs in his system.
In short, Scientology's hatred of shrinks is a reflection of Hubbard's hatred of shrinks who told him that he was a barking moonbat.