This type of opinion is the privilege of someone who has never dealt with sexual assault or rape. You can like what you like, but understand that it's not so easy for everyone. Outside of personal experience, rape is also an overused literary trope to get the two main characters tangled together, and the way it's often portrayed on yaoi belies a juvenile misunderstanding of how sex works.
Whether it's pointing out a tired and ineffective trope, or a call for accurate representation of a violent act, criticism of the use of rape in media is perfectly fine, and it's unrealistic to expect everyone to separate the horrific reality of rape from fiction.
Guys even if this started with rape, it is fiction which means that reality rules do not apply here so plz pay attention to their sweet relationship