It's well-documented that if a survey asks a person "have you ever raped someone", the every respondent will answer "no". However, if you ask someone questions like this, some respondents, in the same group that said "no" to rape, will answer "yes":
1) Have you ever attempted unsuccessfully to have intercourse with an adult by force or threat of force?
2) Have you ever had sexual intercourse with someone who did not want you to because they were too intoxicated to resist? Source: https://yesmeansyesblog.wordpress.com/2009/11/12/meet-the-predators/
Given that, yes. He's definitely a rapist. He just doesn't think what he is doing is rape.
I think Rich Homie is a rapist because his defense of his lyrics was stupid. Heard him on Hiphop Nation on sirius talking about "he's too small to rape to rape a woman". Which leads me to believe that if you polled the women who he's slept with you're likely to find some sex under some murky circumstances if not flat out unreported rape.