He didn't admit to sexually assaulting anyone, he just said that as a star and celebrity girls in that environment will go for that sort of thing, "And when you’re a star, they let you do it" he hasn't said anything he had specifically done, and if they are letting you do it then it isn't sexual assault - how come none of them have ever come forward?
For all you know it could have just been him trying to sound cool in front of the other guys, he didn't "publicly admit to sexually assaulting people". You talk about him having a way with wording yet you are doing the exact same thing, how does a private video where he didn't even mention anything he had specifically done become a public admittance to sexual assault?
Sex tape is just people having sex, the tape was recorded AFTER the actual episode and even if she didn't post it her self it can still be considered as that.