I know you are just being accommodating in debate, but there is not a chance in hell that it's true.
If you want to symbolically blow up a buiding you put some dynamite in it. It's simple, does some structural damage and won't hurt anyone not near the explosion. Remember the Greenwich Village townhouse explosion? The Weathermen were assembling a nail bomb (dynamite wrapped with roofing nails) that blew up on them. The sole purpose of adding the nails is to kill people. They have no other use in bomb making.
They had planned to use this particluar bomb at an NCO dance at Fort Dix. They are lying. They meant to inflict the most possible bodily injury on people, and they are not sorry about it.
Sounds like a "Red Green" way of nailing down your roof all at once.