> None of the Arab countries have ever fully aligned with the US
That's patently false. The Gulf States have been aligned with the US for almost 90 years now.
The US's intervention in Iraq to protect Kuwait in 1991, to overthrow Saddam Hussein in 2004 (the way Kim Jong Un is lampooned in American media is how Saddam is still lampooned in Saudi media [0]), our backing of Saudi-aligned Hariri in Lebanon, and various other foreign policy interventions and alignments in Western Asia were aligned with the Gulf States and vice versa.
The difference is,
1. Obama and later Biden decided to cut off American support for the Saudi war against the Houthis in Yemen
2. Trump was "convinced" by Rex Tillerson to stop Saudi and the UAE from invading Qatar and hoisting the Thani family with a construction crane.
This convinced all the Gulf States that US foreign policy can no longer be trusted, and they need to be like Qatar and build their own alliances with regional powers.
[0] - https://www.facebook.com/masameer/videos/%D9%83%D9%8A%D9%81-...
OP did write "fully aligned".
The US is increasingly turning in to a religious state. Most of the Middle East are people who are part of a religion fundamentally in conflict with the religiosity of America and vice versa.
Ridiculous to me as I don't subscribe to any of this, but oh well.
More fundamentally, the people in those places strongly oppose the U.S. regardless of the alliances of their government. They’re religious and hate the U.S. for supporting Israel. They hate the U.S. interventions in middle eastern affairs. They often have strong sympathies towards socialism and hate the U.S. opposition to socialism.