Programmers used to be a migration target, but far too many Stack Overflow users have no idea what's on topic for us and were voting to migrate any old rubbish which we subsequently had to clear up.
It was (and still is) often users will little or no reputation on Programmers that are suggesting it as a possible destination.
To prevent this the option was taken off the migration dialog.
If you really think that a question would be a better fit for Programmers then flag it for moderator attention using the "other" option. If the moderators agree (they have a pretty good idea of the type of question we want) they'll migrate it. But, as Brad says in his comment it would have to be a really well written question.
NOTE: This only applies to questions less than 60 days old. Older questions can't be migrated by anyone.
In case you are wondering - I do know what I'm talking about