Was my employer in the right for giving me a correctibe action with sexual harassment attached.

I work at a large company that has around 8500 employees. There was an email that was going around. This email was sexual in orientation but had NO pornographic images included. The email was tracked and anyone that received it was either suspended or written up. My question pertains that I received it, did not forward it, did not solicit it, did not provoke it, and only replied "that's funny". yet I get a corrective action that includes Sexual Harassment and now have that label and statement in my file. Am I in the wrong or was this taken a bit to the extreme? Do I have a case to have it removed from my file? In my corrective action form I stated the following: I did not circulate said email nor did I display it anywhere. I also did not reply in a manner that was sexual in nature, there was no physical advance of any kind. I did not solicit said email or provoke anything in a sexual manner.