Yes, and the anti-USSR groups used their power to imprison, smear, seize weapons from, and attack USSR-aligned groups.
It wasn’t a “betrayal,” it was a conflict in how the war should be fought. The Anarchists tried to stick to decentralization even within the context of war, and lost. Had the Anarchists adopted a more Marxist line, they may have succeeded.
What’s your understanding of the entire situation? Are you suggesting that it was going well until the Communists backstabbed the Anarchists? Taking a real, materialist analysis of the situation is necessary. Historically, Communists and Anarchists have had uneasy alliances until differences in organizational theory lead to friction and then conflict.
I don’t know how the war would have gone if those events hadn’t taken place, but it seems to have undermined the strength of the popular front. And from what I’ve read the anarchists were sufficiently organized. The type of Anarchism popular amongst the Spanish was a syndicalist strain very different from the hyper-individualism people expect from anarchists today.