The consequences of bad actors in insurance issuing are much more severe than bad hairdressers or bad cooks.
A bad hairdresser can slice off my ear and a bad cook can poison me.
In finance, it's incredibly easy to make a living by acting in bad faith. You can offer insurance with no serious intention to pay out, and tie up claims in bureaucracy and legal loopholes.
Good regulation should go some way to minimising bad faith actors.
In fact the industry seems quite scammy anyway. But it would be much, much more scammy - to a criminal extent - with no regulation at all.
Both of which require licensing.