The screenshot is very helpful. Those do appear from a cellular provider without a way to remove them. It is possible that your current cellular provider still uses those networks. For example, since Mint mobile uses T-Mobile towers, those customers will see "t-mobile" and possibly "TmobileWingman" as Managed Networks. They seem to be linked to the SIM card and go away if the SIM card is removed.
By tapping the info buttons there is an option to shut off Auto-Join, but some users claim that the option will turn back on. Sorry I do not have a useful explanation for why they show up and why you cannot delete them, so maybe another user will be able to provide more insight.
I can say that they are not unusual and would be interested to know what Managed Networks are found with other cellular providers when they go to Settings > Wifi > Edit. I can confirm that with my T-Mobile provider, I have "t-mobile" and "TMobileWingMan" listed as Managed Networks.