Final answer:
Haymitch thinks it was a good idea for Katniss and Peeta to hold hands during the opening ceremonies because it creates an image of unity and cooperation and can help them gain sponsors and sympathy.
Step-by-step explanation:
The reason Haymitch thinks it was a good idea for Katniss and Peeta to hold hands during the opening ceremonies is because it creates an image of unity and cooperation between the two tributes from District 12. In the Hunger Games, the tributes are pitted against each other in a fight to the death, but holding hands during the opening ceremonies can give the impression that they are allies, which may encourage sponsors to support them. It can also help Katniss and Peeta gain sympathy from the audience, as it shows a bond between them.