ETC has hardforked since then also, and will hardfork again in order to defuse the upcoming difficulty bomb. Hardforks, although not ideal, are needed at this point in time in order to facilitate technological progress
The issue is the purpose of "The DAO" hardfork (in practical terms, a bailout) and how it was done (destroying Ethereum's blockchain immutability).
One side claims the blockchain immutability has been breached by draining the black hacker's DAO.
The other side claims, it hasn't been as there has been no rollback of transactions. In that view, it was just an additional special case rule added to the code that removed the usual restriction for one specific address.
Whatever side's opinion you share, there is one good thing that has achieved by this hard fork. The community has been split along those lines and the group that went Ethereum Classic is for the most part no longer involved with Ethereum.
Besides small bickerings on Twitter, there is no drama about this anymore and the Ethereum community is no longer concerned about this event (although not the obvious problems with the complexity of smart contracts but that is an on-going effort).
Imagine if Bitcoin would have split up along the SegWit / Big Blocks lines. We wouldn't have had a standstill for 3 years and we would have been spared that constant drama.
I was not invested in TheDAO but supported the fork mainly because (1) to anyone who's not a blockchain purist, if you can recover a stolen $50M you obviously should, and (2) it was early days, and the precautions the contract authors should have taken were undocumented and basically unknown to the community, so I thought more leeway was justified. Even the official documentation had similar flaws.