There aren't rules for this in the rulebook, it's more a unwritten rule you don't have the host of league where you don't particapate in, because that's just weird and useless.
The host of the league is not required to be part of the league they've created.
However, if they're completely unresponsive or not willing to be a good host, despite being active, I make special exceptions and can set a new league host. At the moment it sounds to me the current host of the league in question knows he is a host and is willing to manage it.