Is it permissible to adopt the view of Imam Al-Shafi'i regarding the permanent purity of semen, despite the fear of falling into blameworthy cherry-picking of concessions, given the severe suffering from obsessive doubts concerning matters of ritual impurity?

According to the preponderant opinion of the Shafi'is and Hanbalis, semen is pure, and this is the fatwa. It is permissible to consistently follow the opinion that semen is pure, and this is not considered seeking out dispensations. One must be careful not to follow obsessive thoughts.