Why do some people in a work environment use a middle person to relay their issues with coworkers?

Instead of speaking to that person directly?

Example: All conference room scheduling is done by the Executive Assistant at my job. If there is a problem with scheduling my coworkers will call me to have me relate their issues to the Executive Assistant instead of calling him directly and he will in return do the same thing to have me relate his response to them...

Exe Assistant: "Haven't groups met in the spiritually room before? I got a call that a group I scheduled today couldn't meet in there?"

Me: "Yes, we had a group meet in there. But I don't know you have to speak with the Resource Center Director"

Exe Assistant: "Well the group I scheduled will be here shortly, can you check and give me a call back."

Me: "Sure"

RC Director: "Yes a group met before but NO that room is not allowed for scheduling purposes" "They can meet today but NO MORE"

Me to the Exe. Assistant: "She said they can meet today but NO MORE!"

Exe Assistant: "This is going to STAFF!"

I think its one of two things, either they don't want to confront the person responsible because they are uncomfortable with it, OR they find you easier to deal with and feel like you will get a better response then they would. If you do not want it to continue, send them directly to the person responsible and tell them you are unable to do so and that they need to handle it themselves, as this is not your area of responsibility.

It depends on what position you have, if you are the admin for the area then you have the responsibility of the scheduling and they expect you to resolve these conflicts. OR the people have had a bad run in with the person before and don't want to face them cause of this, this person may have an attitude that they didn't do anything wrong and never do. You must have the personality to be able to resolve conflicts without upsetting people, this is a very good trait.