To be precise, the statement "Any action involving PTT before obtaining a license is illegal! Remember, remember!" is problematic.
Yes, operating a ham radio requires a license, regardless of whether you are only receiving or transmitting. However, when you are only receiving, there is typically no regulation, so this falls into a gray area.
Furthermore, there is also the issue of "turtle butt," which refers to using amateur radio for communication with non-amateur radio stations. Amateur radio stations are only permitted to communicate with other amateur radio stations, and only in emergency situations such as major natural disasters. In these cases, amateur radio stations can communicate with non-amateur radio stations, but the content of the communication must be limited to urgent matters directly related to rescue and disaster relief. This includes both receiving and transmitting signals, so using amateur radio to receive communications from aviation, railways, or ships is theoretically prohibited. However, this falls into a gray area where no one enforces the rules, allowing for clandestine use in the short term.