How come listing agents struggle to explain their value

I recently reached out to five different listing agents to list two different properties I want to sell. I mentioned to them that my past experience in selling was via Redfin where the listing fee was 1.5% and asked them to quantify in dollars and cents what is the additional value if they commission is higher. Many made up fake news answers stating that I might not have a good selling experience or have problems at closing. Of course my own personal experiences suggest otherwise 

why can't agents explain their value better?