You can cull these Wi-Fi networks, but you can only really clean them out on a Mac. While it means you don’t have to search for or remember login credentials when you connect to a known Wi-Fi network on a different device, it can lead to a surfeit of Wi-Fi networks stored in your keychain and potentially allow you to unknowingly connect to a Wi-Fi network that might not be secure. Your Apple device’s ability to remember previously connected to networks can be both good and bad. Whether you connect to these networks with your Mac, iPhone, or iPad, miraculously, your devices will remember these networks and sync them via iCloud - so your other Apple products can access them too, if you use iCloud Keychain. If you travel regularly with your Mac or iOS device, you likely find yourself connecting to new Wi-Fi networks: at airports, in train stations, in hotels, restaurants, pubs, or at clients’ offices. How To How to Remove Wi-Fi Networks from Your Mac and iOS Device
