Realize that most of them are playing grade 1 music on stage, strong programs reading grade 2s.
Think about how much time and rehearsal goes into preparing those grade 1 pieces to make them sound like a band. Think about how much blocked parts and melodic-polyphonic lines are in the grade 1s that are written well.
Then think about what is expected of them when they walk into sightreading with that in mind.
Now I haven't gone to contest yet, but I am writing exercises that don't sound super musical or blocked shaped for my band to practice with.
Because I'm going to do what it takes for my band to be and feel successful.
I'm going to do my job and hope for the best for my students by preparing them.
Two edged sword; yes do your job. But also consider what I said in that first paragraph.