Yes a tourist can still get medical marijuana in Delaware as long as they already have a medical marijuana card. You will not be able to go to Delaware and apply for a card, but if you have one from your home state and you should be able to find a dispensary that will sell you medical marijuana.
Recreational marijuana use is not legal in Delaware. However, there is a decriminalization of medical patient use. The penalty for getting caught with possession of marijuana is a $100 civil ticket fine, that can be paid just like a parking ticket. Also, there are no legal dispensaries or establishments that sell marijuana.
Yes, the laws are different for locals vs. people traveling to the state. There is only one medical marijuana center in Delaware and it is known as the compassion center. There is no reciprocity of the medical marijuana laws from other states in Delaware thus the state of Delaware does not honor out of state marijuana licensees.