You obviously have no clue what the line "I'm a screamer", actually means. But don't feel alone, this will go zooming over the heads of 99% of the audience. Crockett is actually warning the Mexican' that they are killing someone who is very important.
Per Mysanantonio.com : "Stephen Hardin, a professor of Texas and American history at Victoria College and a consultant for the film, explained the context of being a "screamer" in the 19th century.
"I don't think people are necessarily going to get this, but in the 19th century, being a screamer meant, 'I'm an important person, I'm a stud, I'm a person to be reckoned with,'" he explained. "It doesn't mean he's screaming like a girl."
I certainly "have a clue" as to how Hollywood revises the courageous portrayal of American historical characters.