This is a classic example of a member of staff who is completely ignorant about the inner workings and background work that goes on to ensure day to day functioning of an organisation as a whole entity.
PR and marketing, for example, deal with hundreds of media enquiries, publicising of public health messages, organisational reputation, engagement with specific patient groups, organisation and maintenance of intranet / staff communications etc etc.
As another example, Improvement and culture/diversity teams are absolutely needed to drive cultural change within the NHS as well as represent and engage with cultural / ethnic minority patient groups, educate the workforce on different cultures and the impact they have on how we carry out our job, contribute to diversifying the workforce and contributing to improvements in staff wellbeing. Have you not seen the damming reports on sexual harassment and misogyny within the NHS?
Event organisers in my Trust are either those who organise / manage clinical cover for large events such as premier league football matches, music festivals, royal visits etc etc. or those who organise smaller things like school, youth group visits, public health events such as restart a heart, 999 family days etc. Again, roles that are required if these events are to remain in place.
Roster coordinators are essential to ensure cover is planned according to operational need and projections. This includes managing annual leave, roster changes, organising relief and overtime shifts, scheduling staff on to training and backfilling their line…etc etc.
Of course, there are some roles that could be combined, left vacant, or not exist at all but none of your list would be one of those.