Like @Dra508 said, read the article. 77 people sentenced to death since the Federal death penalty was reinstated in 1988, but only 3 have been executed. The government doesn't do anything fast, if ever.
The Jury did not likely use their personal feelings, but used the sentencing guidelines provided to them (otherwise their decision could be easily overturned). The big kicker here was the footage of the Defendant placing a bomb directly behind some children without a look of care on his face.