More and more restaurants are taking the time to ensure that their menus are friendly for people with specific dietary needs or preferences.
Regardless of how you may feel about the latest food trends, having options on their menus is good for the restaurants' bottom line because it increases the potential customer base, and gives more options to people with specific dietary needs.
Are some of the most vocal vegans, vegetarians, anti-gluten folks, etc. kind of annoying? Yes, but most are just trying to live their lives and maybe have an option when everyone else in their group wants a bucket of chicken.