Why did the Ethereum community split into Ethereum and Ethereum Classic?

Ethereum Classic (ETC) was created out of a philosophical and ethical disagreement in the Ethereum community that aggravates controversy till today. In 2016, a major cyber security attack targeted a third-party app running on the Ethereum (ETH) network, resulting in the theft of 3.6 million Ether (ETH). In response, the Ethereum network went through a hard fork, in essence, to reverse the stolen funds to their original owners.

Contrary, some minority users who were against a hard fork kept using the original ledger to preserve a 100% immutable ledger. Basically, the two blockchains differed in only one way: one maintained the record of the hack and the stolen funds, while the other created a new ledger devoid of the hacked record. The unchanged blockchain became the Ethereum Classic, while the new fork maintained the Ethereum blockchain name.