why does my airdrop have no settings control

I am having problems getting AirDrop to work between my MacBook Pro (15-inch, Mid 2010) and my iMac (Retina 4K, 21.5-inch, 2017). I have checked compatibility. I have toggled wifi and bluetooth on and off. I have made sure they're both on the same wi-fi. The problem seems to be apparent on the Airdrop screen for the MacBook Pro, screenshot below. There are no settings for discoverability. Does anybody have any idea why I can't control the settings (Everyone, No One, Contacts)?