I never understand these requests, especially for an account with no activity.

What are you trying to accomplish by deactivating your account? If you don't want to use it anymore, just don't use it. It won't do anything by itself, so it would be the same as if it were deactivated.

If you think someone else might use it, you can change your password. If you're concerned that you might use the account when you're drunk or something, you could change the password to something random or have us ban the account.