My guess is that they're talking about exacta prices that are out of line with the win prices of the horses involved.

For example, Horse A might be 3/1 in the win pool, but someone armed with a computer (and complete, last-minute exacta pool info) might find that, by playing all of the exactas with Horse A on top the right number of times, they can guarantee themselves a payout of $1,000 (if Horse A wins) for only $200, effectively getting 4/1 on Horse A through the exacta pools. If the exacta pools were in line with the win pools (a so-called "efficient" market), the exacta prices on Horse A would be lower, so that they'd have to pay $250 to get $1000.

It's easy to imagine why exacta prices would be screwy. There's just too much information to process, espcially with large fields (the GM said Tampa has an average field size of 10), so I assume that bettors follow some shared strategies that result in exacta prices yielded by those strategies being too low, and other prices being too high. I've never looked closely for patterns, but I have noticed, for example, that exactas where a trainer's uncoupled entry runs 1-2 tend not to pay very well.

You're right that there's no romance in this kind of stuff, but people betting big dollars aren't in it for the romance.