Orbital rocket technologies are highly controlled. SpaceX is not independent. It's a government contractor and its employees are under direct government supervision and control for permission to develop/access these technologies. Do you really think the military would let technology which can easily be used as the vehicle for an ICBM be available as public knowledge?
Congratulations, this argument is known as "moving the goalpost". First you asserted that all rocket technology is classified military tech. When the commercial firm SpaceX was brought up, you modified your argument to be "classified military tech and also anything affiliated with government projects even if they also launch purely commercial satellites." Classic FE tactic.
As for tech that ICBMs use - this tech has literally been public knowledge since 7th-century China. You've been confused about what an ICBM is before. It stands for "Inter-Continental Ballistic Missile". It is just one type of weaponized ballistic missile, on a continuous spectrum with Battle Range Ballistic Missile on the lower end, and includes things like Theater range Ballistic Missile.
Ballistic Missiles have literally been used since the dawn of civilization. Trebuchets are a Ballistic Missile system.
Let's break it down, to give you some future clarity when using ICBMs to somehow try to debunk a globular earth (or prove that ICBMs don't exist? Something like that?). Here we go:
- Inter-Continental: Can reach another continent. In other words, has enough range to cross an ocean or sea.
- Ballistic: Moving only under the force of gravity. Free-falling. (Or in this specific context, following a parabolic trajectory governed solely by gravity.)
- Missile: An object forcibly propelled. In this case, by a Newtonian rocket engine.
If you read "ICBM" backwards, you get a better idea:
- A rocket forcibly propels a payload (e.g. a bomb) off the ground, eventually reaching a pre-calculated angle, direction, altitude, and speed.
- The rocket then stops and detaches from the payload.
- The payload then falls back to Earth on a predictable and pre-calculated parabolic path, hopefully to the intended target.
I had a friend in middle school that literally harnessed ICBM technology, and I'm pretty sure he wasn't working for the military, or part of a grand global conspiracy. He fired a payload (a plastic figurine with a parachute) at a crudely "calculated" angle and known burn duration, to deliver it to a target. (Granted the figurine wasn't really ballistic once the parachute popped, but not too different than passive aerodynamic steering/braking tech.) The rocket technology used was identical in concept to ICBMs - an impressively large newtonian rocket accelerating an aerodynamic cylinder, fitted with a rounded conical nose and stabilization fins. The only difference was choice of propellant for practical safety, economic, and scale concerns. And also size, range, and purpose.
Ballistic missiles by definition do not enter Earth orbit, even if they may extend beyond low-Earth orbit for very long distances. That would be extremely impractical, and require additional fuel and significant leap in technological capability, to de-orbit on target. There are/were fractional-orbit missile systems, and orbital missile systems are certainly possible if not existing. But "ballistic" is not part of their name. A ballistic missile is literally just lobbing a bomb from the ground, to the ground. (Though that may some day be expanded to include a bomb that eventually falls ballistically after using rockets to de-orbit from an orbital launch platform.)