Why does Pedigree think that "rubber" is a bad word?

I am on a href="http://www.pedigree.com/oralcare/denture-your-dog.aspx" rel="nofollow"http://www.pedigree.com/oralcare/denture…/a , and if you do text-to-speech and put in rubber, it says don't use curses, or if you use rubber in a sentence it does a beep. Why?