Didn't she state that one of her most popular songs is about using ecstasy? And isn't that illegal? As far as the advice to build a club and party at home, it would keep him off the street, but maybe "Stop acting like a spoiled, out of control brat" is better advice.
Using ecstasy is illegal, but as far as I know, there's no law against singing about illegal activities. Unless there's evidence of her actually using drugs herself or committing other crimes, rather than just singing about them, then I don't see any hypocrisy in her statement that "I'm doing a lot of [bleep], but I'm not doing anything illegal" or in suggesting that Bieber should do the same. Bieber doesn't seem to be listening to any normal, law-abiding adults about his behavior, so maybe another wild young celebrity pointing this out is exactly what he needs.
Also, this was not clear from the text, but Leno was the one who asked if she had advice for Bieber in the video. This wasn't an unprompted statement from Cyrus, as if she thought she was some great authority on behavior. It was an answer to a direct question.
No, I mean the song is about the fun she's had while on it, not just about it in general (isn't the line something like "We party with Molly"?). I actually don't have a problem with her. She's not to my taste but she's an adult so live and let live. That said, I don't think it makes much sense to admit to the fun you've had while high and then tell someone else to keep it legal. But hey, I could be mistaken about the drug thing. I don't really follow her so all I've got to go on are headlines.
Were you interpreting the song as an admission of drug use, making her statements hypocritical? Or are you saying it's hypocritical to make money off the image of drug use (by including it in her songs, regardless of whether she's done drugs herself), while telling another artist he shouldn't do anything illegal?
If the former: I'm not familiar with the song itself, but I guess I just generally view songs as fiction. I don't assume what is described actually represents the singer's (or songwriter's) own life in any way, unless there's clear evidence otherwise. For me, writing/singing in the first person is a stylistic choice, not a indication that the singer/songwriter actually experienced what is described. I assume that a lot of songwriters, like authors, write what they think will be interesting or popular among their fans, or what will support their "image," not necessarily having anything to do with their own experiences. So for me, a reference to "partying with Molly" just indicates that she thinks her fans will like that. Unless there was outside evidence that she does drugs herself or it was a detailed description of the drug's effects, I wouldn't take it as a strong indication that she actually does drugs.
If the latter: I can see how it's a bit hypocritical to profit off of songs about drug use, but tell someone not to do anything illegal. OTOH, I think a message along the lines of "Dude. It's fake. It's a show. Just because the fanbase likes 'bad-boy' or 'bad-girl' personas doesn't mean you should actually
risk your life or risk getting thrown in jail" is a pretty appropriate message, for Bieber and
for their fans.