GPM and CLI - installation required?

I am using Rochen shared hosting, and get a "Permission denied" on the terminal when I try to use the GPM commands. Their support said:

"I have checked and the problem you are facing is because gpm is not installed on the server, I don't think we can install this for you, But I will still forward this ticket to our Engineering team to see if it is possible for us to install this for you on the shared server."

Is he correct? After I read the Grav documentation learn.getgrav.org/webservers-hosting/shared/rochen I got the impression that this would be sort of plug and play with Rochen shared hosting.

GPM is a PHP shell script installed in the bin/ folder inside Grav. The support I think got "tricked" in thinking it's an executable that must be installed on the server.

The problem looks like it has no executable permissions.