This is just another theory, but it seems to be pretty consistent
So why hard forks are good for Bitcoin in the long run? In short, because they allow to get rid of rogue miners. Yesterday I read a letter signed by major cryptocurrency exchanges, and they declared that they would list Bitcoin forks (if such should emerge) as just any other altcoin out there. Basically, it means that any attempts to hard fork Bitcoin will massively and almost instantaneously backfire on those supporting them. People will naturally stick to the trusted version, and treacherous miners will be wasting their resources on mining a useless and worthless coin. In this way, they will necessarily leave the grand pool of genuine Bitcoin miners, and there will be more consensus between those who will remain in respect to future evolution of Bitcoin. Thus, those pools which support hard forks will voluntarily leave the scene and free space for other miners, likely more friendly toward gradual development of Bitcoin. That's why hard forks will come out as good for Bitcoin in the long haul
Some said that forks can destroy bitcoin then this thread showed that forks will help bitcoin in a long run. Therefore I conclude that forks neither help bitcoin nor destroy bitcoin in a long run. If the forks will become shitcoin then the reputation of bitcoin will loose. On the other hand, those people who entered this fork may leave and they will stake to the original one, bitcoin. Now I know how forks work and what its value in bitcoin and other cryptocurrency.