Cloud SDK is pre-installed on the public images provided by Google. It is a useful tool when your VM needs to interact with other resources in your project.
I am not sure what is the reason you want to uninstall it. When you create a VM, you are given the possibility to define the service account and the scopes that will work with that VM. That service account will be the one authenticated on the gcloud tool running in the VM. That account and the scopes of the VM will be the ones limiting access to other resources. For additional information check this article
You can always choose not to link a service account at the creation time of the VM. If you do that, Cloud SDK will not have any credentials to access any other resources in your project.
gcloud auth list
No credentialed accounts.
To login, run: $ gcloud auth login `ACCOUNT`
Check this discussion which also addresses the same topic.
If you really want to remove Cloud SDK, you can follow the steps provided here