All chainforks are not hardforks. Short chainforks happens every day. Usually because miners can't distribute their newfound blocks fast enough. This one was caused by a malicious miner not validating blocks, and mining on top of an invalid one. It disappeared as soon as the correctly validated chain overtook it. This only show the dangers of one miner controlling too much hashrate. All nodes, new and old, accepted the correctly validated chain as soon as it overtook the bad chain, and nobody were forced to upgrade anything. (Those who hadn't upgraded were potentially vulnerable to double spends however, as with all chainforks when you don't require enough confirmations. This is a good reason for merchants to stay up to date.)
The August 2010 fork was much longer, btw. That fork was caused by a bug which had to be fixed for the nodes to reject the faulty chain.
A hard fork is different. In a hard fork where the fork has a miner majority, the two chains will live on in parallel. Correctly validating nodes will never switch to the fork. The so-called "Classic", "XT", "Unlimited", etc forks are especially dangerous, since upgrading won't help either. There will just be different coins, and you have to make a choice of one of them. Due to incompetent fork developers, you can't even run one of the other coins on the same computer at the same time as Bitcoin Core, since they demand to bind to the same ports. Constantly keeping up with which fork to use this week is too much for most users, and since their SPV wallets will be rendered useless, they will probably just try to get rid of their coins ASAP. It would be sad end for Bitcoin, I think.
If some competent developer should think about forking bitcoin, he should start
here and get 100% consensus first. There are many good reasons for a fork. Forking for a simple block size change is just dumb, and most people see that.
Hard forks are indeed dangerous if there is no major consensus, but if there is major consensus like 80%, then it is safe. Since the minority fork will just become an alt-coin with much less value (hash power decide value due to arbitraging)
We already have hundreds of alt-coin exists in parallel with much less value but similar code to bitcoin. The reason majority of people don't care about them is because they believe the anti-inflation promise is given by limited total coin supply, so they support only bitcoin to make sure the coin supply is limited in bitcoin ecosystem
Follow the same logic, in the event of a hard fork that bitcoin fork into two chains, majority of people would still support only one bitcoin fork to make sure the total coin supply is limited
But the problem with soft fork is that it forces minority miners to upgrade if they don't comply with new rules, otherwise they will never be able to mine any coins. This is like communist party throw people with different political ideas into prison to make sure their politics are always widely adopted by every one in the society
Bitcoin community consists mostly of libertarian type of people, and it is unavoidable there will be different views, it is impossible to reach consensus 100%, so when the majority wants to move to a new implementation, the minority miner must have choice to not change, if that fork will be succeed economic wise is irrelevant, the freedom of choice is the most important reason people come here