.. because that's what that word means? You, the SETL, have the authority to call them, the GM Experts, for backup. You are empowered to do so.
I, the GMTL, do NOT have the authority to call them, the Guest Advocates, to help push pillows. I am NOT empowered to do so. My ETL-GM might. Or the SD. Or maybe your ETL-SE might offer the help, but Modernization does not afford me the right to take your TMs like it affords you the right to take mine.
And really? I just linked a page of the guidebook. Business needs. It is the job of everyone to do something that needs to be done, regardless of their position. The difference here is that the person making that call needs to be higher up on the totem pole than you, the SETL, need to be to call for backup. Even Service Advocates can call for backup. Any GM Expert or Food & Beverage Expert or SPS Consultant calling the Front End for help is going to be laughed at.