I wrote a long comment but basically it boils down to: 1) "backend" developers have always devalued front end to try to protect their (sometimes easier) cushy jobs and salaries involving slower-evolving technologies from often younger "frontend" developers, 2) "frontend" and "backend" without a lot of context are basically meaningless at this point, and 3) if someone is really good at CSS and wants a title with the word "Engineer" in it, I think they deserve it.