Are the U.S. equities markets no longer “stable and predictable”?

In light of today's fortuitous announcement by Donald Trump about peace talks with the Iranians, which the Iranians subsequently denied, and which caused WTI front month oil futures to drop over 10% and a massive upswing in SPY, I think it is time to start asking the question of whether the US equities markets are still "stable and predictable".

It seems rather coincidental to me that each and every time WTI front month oil futures exceed $100, the President suddenly "remembers" a forthcoming peace deal and takes to his social media platform to "Truth" it. This has happened two times, followed two times by Iran's rejection of the claim, followed two times by bombing campaigns the same day by the U.S. and Israel against Iran.

One of the reasons for divestment from China I often heard was that Chinese equities could not reflect true valuations of companies, since the price of those equities was subject to the whims of the CCP.

Have we reached that point in the U.S.? Can we trust that U.S. equities are stable and predictable when a single person can make disputed claims on their private social media platform and introduce wild swings and unprecedented volatility?