Especially given that Mike May is hardly a friend to developers, while Jeff Dion has no official acts which show he isn't the developer's best friend.
Anyway, here it is, straight from Jeff's own web site:
Developers for Mike May???
December 16th, 2006
There’s a rumor flying around that Mike May has already received the endorsement of an influential group.
We’ll keep you updated as we learn more.
And who is that group? From the link, it's "Developers for Mike May":
The Developers for Mike May website is coming soon. Please check back. Paid for and Authorized by Dion for Supervisor.
So Jeff Dion has set up an organization, Developers for Mike May, and Jeff says his group endorses Mike May for Supervisor.
When a candidate endorses his opponent, you should listen to him. Even if his reasons are ignorant.