When a large employer in the UK proposes a significant number of redundancies, it is normally expected to go through a consultation program with its staff - the aim is to try to find a way to redeploy existing staff in other roles, and give staff a chance to make plans as to what to do next rather than finding a surprise redundancy notice on their desk.
Easyjet are just following these procedures and making sure they cover themselves from an HR standpoint.
A similiar process happened when the Dortmund base was closed