The article you link is the worst kind of telling of history: overflowing with bias, preaching and pontificating and making moral judgments left and right about things that happenned more than 2000 years ago. It is an internet rant, designed to provoke clicks and outrage, and its only reason of existence is the existence of the film, 300, a fantasy, that presents a fantastical image of Sparta, that the author then proceeds to deconstruct as if it were reality, or as if anyone claimed was reality. It is one gigantic straw man.

Instead of consuming one person's opinion, second-hand, why not read the original historical sources?

For example:

The Polity of the Athenians and the Lacedaemonians, by Xenophon

https://www.gutenberg.org/ebooks/1178

The History of the Peloponnesian War, by Thucydides

https://www.gutenberg.org/ebooks/7142

History, by Herodotus

https://www.gutenberg.org/ebooks/2707 (Volume 1) https://www.gutenberg.org/ebooks/2456 (Volume 2)

On Sparta, by Plutarch

https://www.amazon.com/Sparta-Penguin-Classics-Plutarch/dp/0...

And so on. Read history; and make up your own mind.