Communist state was heavily relying on military, just like fascist Germany. Because communists knew only way for their plan to work is to conquer the whole world. Just like capitalism tried to eradicate communism, same was happening on the other side.
Capitalism will always win against communism in fair battle because it is relying on basic instincts while communism needs special circumstances to succeed. Communism can only work in vacuum, without other options or opinions present. It is ideology with clear goals, that resembles religion because it serves like life guide. Only freedom you get in communism ideally is freedom from oppression by higher class. You sacrifice all other freedoms for it. In the end you're still oppressed by higher class because our society, just like ant society is built around vertical hierarchy. There needs to be different kind of society for ideas like communism to work.
I think that somebody wrote that Lenin tried to make such society by giving power back to the people, so called decentralized government or no actual government where every group of people governed by themselves. It backfired of course, because as soon you do that people start oppressing each other on micro level, so called local Lords pop up (happens in every chaos like war in Ukraine for example).
So yeah, for communism to work we need to be optimal people with vast knowledge and 100% sane. But when (if) time comes when every adult human is like there would be no need for governments or ideologies. Communism is more like a path to that state than actual working government model.
Why people stand for it in such vast quantities? They want huge change because it gives them possibility for better life. Every massive change does that to society, nouveau riche pop up everywhere.