I don't know if it is like that on App Store too but I agree with you on Play Store. There are really many apps that fake comments are distinguished easily in the comments below. We should really be careful before downloading an app. If you don't trust it fully, I don't recommend using it. They can access your private things after giving some permissions to the app and do things that you wouldn't like.
But with most recent android versions you can edit the app permissions by entering into app management setting so you just need to have a closer look at the given permissions to unknown apps and if it is having any permission which is totally unnecessary to the utility of the app then you can consider it as spyware.