Why were the Spartans cruel?

Answer 1

They were a military state, focused on creating supreme warriors. However, their state was also focused on doing "what was right"... Much like the greek custom of Xenia. One philosopher (Xenophon) once noted that at an olympic games, an elderly man was looking for a seat and the Spartans stood up for him to sit down. The Greeks did not stand up but instead applauded the Spartans for doing so. They also had equal rights for women. No other state in the classical world had this type of power for women. Even Egypt, who had female priestesses and pharoahs did not let all women have equal power.

So they weren't that bad. They just chucked away feeble babies. But they were often adopted by Helots who lived in the mountains.

Helots were executed if they got too fat.