apple news share button

Under that Share menu is an option "More ..." which opens the Share Extension in System Preferences. But there is no option there to clear those entries or even to disable the Mail share option (I was going to suggest disabling the Mail Share option, then close News and reopen it to see if it cleared all the emails listed but it does not allow disabling Mail as a share option). I'm guessing they clear out after some time, otherwise the list could grow forever.

Could that be because you recently shared one or more News stories via that email and Apple News is trying to be "helpful" by offering you that option again as a shortcut? In addition to the standard list of options?