Terrorist attacks and deaths-by-ladder should not be compared.
Why talking about lightning strikes and staircase falls in the context of terrorist attacks is stupid (aka "the bathtub fallacy").
Terrorism is different. There are small incidents, but there are also huge ones in which hundreds or thousands of people die. It’s a fat-tailed distribution, in which outliers are really important. It also isn’t stable: Five or 10 or even 50 years of data isn’t necessarily enough to allow one to predict with confidence what’s going to happen next year. It’s a little like housing prices -- the fact that they hadn’t declined on the national level for more than 50 years before 2006 didn’t mean they couldn’t decline. Meanwhile, the widespread belief that they wouldn’t decline made the housing collapse more likely and more costly.