It's what you are being told.
Number of actual Iranians who did those bombings? Zero. Zero.
You can look this up you know.
Heck, the one bombing that they obviously did do, or at least seemed to, Pan Am Flight 103 over Lockerbie, was the only time somebody cut a fart internationally that wasn't blamed on Iran. It just so happened to be on the anniversary of when the US shot down that Iranian passenger plane by 'accident.'
That's it, the one act of terrorism they probably had something to do with, they didn't even have anything to do with that, and they weren't even blamed for it. That's the weirdest part, they weren't even blamed for it, not even mistakingly. They wouldn't be not blamed for anything until 9/11. Even the first bombing of the World Trade Center was initially blamed on Iran till it turned out they yet again had nothing to do with it.
Not that I'm given to conspiracy theories, but I always found it remarkably odd that nobody even suggested for a fraction of a second that Iran had anything to do with 9/11. It kind of seems like they already knew who did it, even before anybody knew anything other than it happening.