First, it isn't dumb, since the route from MSP to MCO is in demand more so than via Baltimore (who wants to go to Baltimore, anyway?

).
Distance flown and actual costs are not what the price is based on. Instead what matters is the demand on the seats. As you know (and for clarification of the statement), many airlines use a hub system. Passengers from ancillary cities converge on a single port for further travel to their destination. As such, each seat
into the hub is important, as it fees the distribution network.
If a passenger is flying
into a hub airport and terminating, they are occupying a seat that could be filled by a traveler transferring to another route/city the airline considers important. This importance could be due to market share, higher paying customers (business travelers), or a feed into an international market. As such, in essence, the terminating hub passenger is taking something away from the airline, so the airline makes it worth their while by charging more.
A better example than MSP is the United and Frontier routes from Colorado Springs to Denver (hub for both airlines). While it is an hour drive from *** to DEN (ok, hour and 15 minutes), the flight costs a couple hundred dollars to terminate in DEN. Much cheaper to drive, even paying for a full price rental car with transfer fees.
In the case above, MSP is a Delta hub, and I think BWI is hub for US Airways and a big transfer point for Southwest Airlines, too. As such, a delta flight just to/from MSP is going to be higher than United, since MSP is a market share issue for United or American, while it is a seat drain for Delta. The reverse is true for Chicago O'Hare, since both United and American have hubs but Delta does not. In the latter case, Delta should price more competitively than UA or AA.
This is why it seems to make no sense for pricing to be the same or more to fly from Kansas City to Minneapolis (or LAX, or Dallas, or Atlanta) than it does to fly from Kansas City to Orlando via MSP (or LAX, DFW, ATL).
Great point, Duds, as the explanation is important, especially for those new to flying.
Personal curiosity question:
As for the routing, may I ask for additional clarification? Is the total route
1) Originating in Minneapolis, stopover in Orlando, stopover in Baltimore, terminating in Minneapolis?
or is it
2) Originating in Minneapolis, stopover in Orlando, terminating in Baltimore?
I ask, since it makes a difference. Sometimes to get a cheaper price, folks will book a ticket with a leg into/out of a hub (or other destination) with no intention of using that portion to save money. Airlines greatly frown upon this, and there may be consequences to this practice.
For instance, bags will continue onto their final destination, so checking luggage isn't a good idea. If the airline finds out, they could terminate the passenger's frequent flyer account, any refunds/rebates, or the remaining portion of the itinerary with no refunds. Finally, they may reroute the passenger due to mechanical, weather, or other delays through another hub than the intended termination point.
Not saying this is what your question was about. Rather, it makes a great point in conjunction with the previous discussion on hub pricing.