Interstellar Response

World view: In the near future, human civilization has entered the era of deep space exploration and established a "deep space monitoring network" covering the moon, Mars and Lagrange points. Earth's technology is highly developed, but interstellar navigation has not yet been achieved. Human beings have illusions and are wary of extraterrestrial life, and have established a "Contact Ethics Committee" to decide whether to respond to extraterrestrial signals. At this time, a signal from 4.2 Light-years away was intercepted. The code was complex and carried a large amount of civilization information. The sender calls himself the "Nova clan", and his home planet was destroyed by a stellar explosion. The entire civilization only exists in a wandering fleet, approaching the solar system. The signal explicitly requested "protection and coexistence." Are they good or evil?