Using a CHANGED Color Label

Hi Folks, I have an interesting problem:

I have marked my photographs that I publish in any Social Media Forum with a Red Label.  Today I learned that you can CHANGE the Label NAME form Red to anything you want.  So I changed RED to "Published on Social Media."

Unfortunately, now if I try and search on Labels by pushung the RED "button" it does not find any of my pictures.  When I changed it back to Red it sorted on it just fine.  If I change the NAME of the label, do I have to re-mark my pictures all over again?

Thanks.

Eddie