Yes, they did say they would NEVER remove a star. It was hard to find it but I found it.
https://www.japantimes.co.jp/culture/2015/07/10/entertainment-news/despite-protests-cosbys-walk-fame-star-stay-honors-scrutinized/#.W2j3hhplCfA
https://imageshack.com/a/img924/3110/0WbBdu.jpg