Security issue reported by @slawkens
All wifi traffic is broadcasted - this means that any nearby sniffing devices can read your traffic. If you're connecting to a page through HTTP over public/unencrypted wifi you can assume that whatever information you are sending and receiving is public - all it takes is an attacker nearby with an antenna to read all that in plaintext. To perform a true MITM by having traffic flow through them, attackers can use technologies like WiFi pineapples or aircrack-ng to force users to connect to their wifi network.
Connecting over cable internet is much harder to intercept/mitm because you're not broadcasting your traffic for the whole neighborhood. In order to compromise this network an attacker will have to gain access to it somehow - either through physical access to a network port, malware installed on a host machine or router, etc. When an attacker has access to a network they then have to exploit that access through attacks such as ARP poisoning or HSRP spoofing. These attacks just MITM traffic - anyone on the network can still sniff (read, but not change) traffic, but keep in mind HTTPS traffic is still encrypted and can't be read.
https://security.stackexchange.com/questions/153148/how-easy-it-is-to-actually-perform-mitm-attack-these-days
