I wouldn't disparage people for anything that brings them to socialism though I def agree, but the question of how theory is practice gets neglected quite often. There's a dialectical relationship between the two, Marxism is what gives us the capability of fully fusing theory with practice, subject with object, individual with the social. We can read theory and commit to practice and learn nothing, accomplish nothing, because we still have the insidious dualist mindset. Everything we learn gets categorized and atomized. We learn words and phrases to signal understanding to others, but understand very little. Feeling accepted is perhaps the first step for the stubborn individual to let go of individualism and embrace socialization, so its natural for new comrades to want to make themselves sound radical, and they should be accepted by cadre and celebrated for their achievements. But of course radical talk and radical action can be quite distinct, and experienced cadre should know how to tell the difference, and challenge comrades to continually improve and fix themselves. I've seen people able to be very inspiring and educated in speeches, but opportunistic reformists in practice. This must not be how comrades develop, this is not self actualization, it is bourgeois affect.

Theoretical study opens up many avenues to understand material conditions, through practical analysis, discussion and criticism. Then, once the actual conditions have been assessed we can take action -- but based on material conditions and not theoretical abstractions. Taking action changes conditions, changing conditions requires more analysis and critique, which may require deeper understanding of theory in order to assess conditions accurately. Once assessed, we act, rinse, repeat. Evaluate and take action, reevaluate, and take another action.

I've seen too many comrades trying to apply the tactics of 1910s Russia to american struggles. They quote Lenin on a particular tactic or strategy, when Lenin was often changing tactics, and rhetoric, in order to most effectively address changing conditions. Too many comrades read Engel's 3 rules of Dialectical Materialism and apply them like an orthodoxy, but have never closely studied Theses on Feuerbach nor unveiled the human spirit that thrives within Marx's works.

So I'm not contradicting you, or I don't mean to, but theory and practice is not necessarily our objective. Marx explicitly called for theory in practice, which means our theory must itself be practical. Theory helps us to see through the illusions, it must not be made into yet another illusion. But IMO therein is the most important benefit of surrounding ourselves with good cadre, they'll call me out on my shit, and help me up when I stumble. Anyone who encourages us to be better, to be more practical, to center the human perspective in our work is following the same spirit as Marx, and it doesn't matter what they've read if they've read anything at all.

But also, its no coincidence that good cadre Marxists are also exceedingly comradely, good natured, fair and fearless. The practice transforms us, so we can transform the world, together.

I understand what OP is saying, but I'm pointing out that it's silly to take a philosophically rich, globe spanning, radical tradition and throw it aside as "a thing stupid children believe", and use that as a thought terminating cliche to not engage with the tradition as it exists in the real world.

You don't have to ascribe to Marxism. I happen to, but I would have posted the same bit if OP was ragging on Anarchism like that as well.

Side note, Cuba has changed quite a lot since Castro. I would encourage you to read up on the rewriting of the Cuban constitution, and the implementation of the new Family Code, both of which happened a few years ago, and are at the very least, interesting.