I don't think it's handling, it the way people are handling and interacting, they are petting, they are basically doing mutual grooming, which sets you up as an equal to the rooster, and there is hand feeding, another behavior done between equals, the problem comes at sexual maturity when the...
If you understood rooster behavior and the hierarchy than you would know that a dominant rooster commands respect and chases submissive ones when he feel like, he doesn't turn his back or allow himself to be attacked, the problem comes from people handling their roosters as chicks, they become...
Cuddling and petting rooster most often causes the rooster to be confused that you are not a part of his flock, he's trying to dominate you now that he's becoming sexually mature, unfortunately it's near impossible to retrain such roosters, you will probably have to put up with him attacking you...