Shouldn't OCD—being an illness like a cold or fever—be treated with lawful Ruqyah specific to physical ailments, while seeking refuge is for Satan, lusts, and sins?

There is no contradiction between the types of legitimate (religious) and sensory (physical) remedies for obsessive-compulsive disorder (OCD). It is an illness that has organic causes, and trusted doctors can help in its treatment. The person afflicted with this disease should also turn to Allah Almighty and frequently supplicate to Him, seeking help through legitimate ruqyah from the Qur'an and Sunnah, for seeking refuge in Allah has a profound effect in treating this ailment.