Why does the oculus rift rollercoaster game make people freak out?

Is it just because these persons can't stand rollercoaster at all? I thought maybe the lack of physical movements deludes the brain and makes you feel bad. I'm searching for people who actually tried the VR-glasses and for people who know something about brains who want to explain this phenomenon to me!
Your brain reacts to virtual reality in a profound way [1]. The hippocampus, known as the "GPS of the brain," is involved in helping you remember your surroundings and track your emotions while in virtual reality [1]. Interactions between the eyes and the vestibular system, found in the inner ear, help detect motion, balance, and spatial orientation [2]. However, the combination of the jerky and unpredictable movements in virtual reality can cause your eyes and ears to send mismatched messages to your brain [2]. As a result, you may feel dizzy, sick, or excited/satisfied [2]. Roller coasters can have similar effects on your body [2]. The combination of increasing gravitational pressure and blood being forced toward your feet can deprive your brain of blood and oxygen, which can lead to lightheadedness, vision loss, and black-outs [2].
There isn't consensus on why people become ill in VR, but it's well accepted that display lag—the delay in the virtual scene keeping up with actual movements—is a key contributing factor [1]. Research has shown that people become nauseous due to a "sensory conflict," wherein visual pieces of information received by the eyes are disconnected from or in direct challenge to information received by the other senses [2]. People standing still in a virtual environment that's moving around them will disturb the brain's equilibrium and cause nausea and dizziness [3].