Why are they illegal? What is your source?

Homeowners can’t put solar panels on their roof to use the produced electricity?

Nope, because of laws written by energy company lobbyists for the "safety" of consumers, so if you're mixing grid and solar on the same site (even if completely isolated circuits) you have to get all kinds of certifications and permits for inverters and breakers installed by certified technicians that make it cost prohibitive.

As I understand it. They banned solar inverters as well as severely tariffing the panels. In some places it's also illegal not to get your electricity from the grid.