Unions believe that they can secure their jobs by bullying their employers and competitors.
If University employees want to have job security then they should perform well at their jobs. If dining hall employees wish to keep students eating at the dining halls then they should do a great job preparing the food. Job security shouldn't come from bullying but from a desire to do the job well and prove that one is needed as an employee. For some reason, union employees believe that they are OWED a job. If they do a good job, they will keep that job.