Why did additional troops join the texan army after the battle of coleto

They were angered by the Goliad Massacre.

Explanation:

During the battle of Coleto, the Mexican army managed to capture hundreds of Texan soldiers. After the battle, the Mexican army drag those army and gathered them to Town called Goliad. Those soldiers were publicly executed for the locals to see under the order of Antonio Lopez de Santa Anna. Approximately, around 445 captives were massacred that day.

This angered a lot of Texans and increase the amount of people who wanted to be drafted as Texan troops to fight against the Mexican army.

the 2nd option is the answer

the answer is tom watson. tom watson created this epitaph because he wanted to increase the sympathy felt by people towards the murder of mary phagan.