Sauron is the reason the palantiri are dangerous, yes, because his influence causes them to mislead and delude the viewer. That happens even when Sauron is not directly influencing the visions. Essentially, when the forces of evil are present, the seeing stones may show the truth but in such a profoundly misleading way that even those with the best intentions will misinterpret their visions and fall prey to misunderstanding. This even happens to Sauron himself.

It's worth noting that by the War of the Ring (the Lord of the Rings story) Sauron had possessed a palantir for around 1000 years. Anyone who knew what a palantir was should have known that they were not to be trusted.

As for how that relates to Palantir the real-life corporation, I'll leave that up to your interpretation.