Sometime users do not want or need all components from GPG Suite. During the install process you can opt for a custom installation.
Follow the installer and once you arrive at step 4 "Installation Type" click the "Customize" button.
The Custom Install allows you to de-select components as desired.
Note: This screenshot was created on macOS 10.13 with GPG Suite 2018.4 so GPG Mail is listed twice, once for macOS 10.13 High Sierra and for macOS 10.14 Mojave.