There can be several reasons why an app cannot be uninstalled from a device.
One possible reason is that the app is a system app that is pre-installed on the device by the manufacturer or the operating system developer, and it is an essential part of the device's functionality. In this case, the app cannot be uninstalled without rooting or jailbreaking the device, which can void its warranty and cause other security and stability issues.
Another reason why an app cannot be uninstalled is that it might be a device administrator app that has been granted special permissions by the user or the device owner. In this case, the app controls certain device settings such as password policies, security certificates, or network access, and it cannot be uninstalled without revoking its administrator privileges first.
Finally, an app may not be able to be uninstalled if it has been installed as part of a package or a system update that cannot be rolled back, or if the app's files and data are shared with other apps or the device's firmware, making it an integral part of the device's ecosystem.
In general, users should be careful when installing apps and only install those that come from trusted sources and have a clear privacy policy and terms of use. If an app cannot be uninstalled, users may consider disabling or freezing it if possible, or seeking help from the device manufacturer or a qualified technician.