All of them. No one is going to guarantee that an engine will work on every system with blazing speed, let alone that you will be successful.
You're taking what they don't tell you, the stuff you can't do, and trying to blame them for it.
If you want to accuse them of lying, then by all means start providing the proof.
Can you make games that work on a large number of platforms, and devices with it? Yes.
Can you make every thing imaginable? Nope.
That part is up to you.