why are kids today fantasizing with communism and similar doctrines?

Because todays generation are given a magic money card. They get mad when it stops working. Debt, interest, how an economy works... These are things that are intentionally withheld in public schools. They don't understand how loans work. Or that the job they want no longer pays enough to support their desired lifestyle.

People who don't understand how the system works, will be, by default, taken advantage of by the system. Their newfound hatred for capitalism is a side effect of it.

If their parents explained how things worked, then they would grow to appreciate it after it gave them money, but in order for that to work, they must first be given parents who had parents who understood it.

do they expect their lives to improve somehow after this "revolution"?

All they know is "Now bad. Future good." Delayed gratification is a foreign concept for many of them, and I why wouldn't it be? Food is free. Water is free. They've never had to work for a day in their life, then suddenly they are expected to do hard manual labor, because nobody told them that would be consequence for not focusing on getting the right education. "Go to school to learn what you want to do!" is the absolute worst advice you can give. They don't want to think hard. They don't want to work hard. So what are they going to do when they go to college? They're going to pick the classes that are easy and pointless.

to become communists to be pro woman rights?

A woman is told she doesn't need help (or a spouse) to have a career. By the time the average person gets that raise/job they want, they will be in their late 20's, early 30's. At this point (as sexist as this may sound to those online in denial) most men don't want to start a family with someone that old, so they end up stuck single. There's tons of data online to back these numbers up.

The resulting conclusion that they come up with... is that somehow the capitalistic job system is to blame for them ignoring biology. The fact is that if a woman wants to have a career she's going to have to focus on starting a family with a man who isn't looking for a career of their own. This man will often be younger than her and less wealthy than her. Both of these things are unattractive to the majority of women.

So this highly successfully woman, who has all this money, is slowly running out of time, and is hating the world because she can't find a "Real Man."

Obviously it can't be her fault for being unable to compromise./s

That's why the feminist movement is slowly inching towards extreme socialistic and communistic ideas. They were lied to. Now they're old and pissed off at the world.