A butane lighter can’t explode “like a stick of dynamite”. It contains fuel but no oxygen or oxidizer. The fuel can only burn as fast as it comes in contact with air. Now, if you put a hole in the side and add a source of ignition you may have a big jet of flame, but no explosion. I threw a lighter into a campfire once, and as soon as a small hole was melted through it flew a few feet into the air under the pressure of escaping fuel and that was it.

The alleged problem seems to be crud from the flint getting into the valve mechanism and keeping it partially open. You put it in your pocket and your clothing becomes saturated with gaseous fuel, which could cause burns if ignited.