Well, only partly. Guys like Immanuel Cellar had worked for 40 years to reverse the 1924 act, along with a parade of leftist fellow travelers. This was just their moment.
The most important thing about Hart-Cellar's passage was the fact that it was the result of colossal lies, such as Teddy The Future Swim Champ's speech claiming that "The bill will not flood our cities with immigrants. It will not upset the ethnic mix of our society". Robert Kennedy predicted 5,000 immigrants from the entire Asia-Pacific Triangle, 'after which immigration from that source would virtually disappear.'
I'll leave it to you to decide if they were just clueless or intentionally lying.
I was waiting to see how many posts before a trenchant comment on the monstrosity that was the 1965 Act.
Only waited until post #13. Not too bad. The situation here is not so hopeless after all. But I hope in the future the first post after any article referencing Hart-Cellar cuts to the heart of the matter as poster Regulator did: The 1965 Immigration Act was and remains 100% pure Marxism. It should be reviled now. And down the road reversed.