People never realize the mentality of the times when the Tudors ruled. While there was no Salic Law, boys are preferred and Henry was no different in that need, he was simply more ruthless about getting one.
he was more ruthless because he needed to be. A son guarantees the succession. A daughter promptly invites the question “who does she marry?”. The Kingdom had nearly torn itself to pieces over disputes to the succession barely fifty years previously. No one was anxious to repeat the experience.