Why does Yahoo refuse to me to forward e-mails I have received. If not acceptable, why even allow them posted?

I received a rather risque e-mail and because I sent it on as a forward, I was deactivated. It was not lewd or decidious. If such mail is not acceptable, why did they allow it to come into my mail box?. I re-entered under another name and now just about everything I get in my e-mail am unable to forward.Example: I received an e-mail yesterday regarding Citgo Gas stations, and being owned by foreign power and was asked to forward it on. The mail-demon would not allow it to be forwarded... Doesn't make sense... Everything comes back as a "permanent error".