People care about decentralization, but we also cannot deny the fact that we also need the centralized system that's for those who need social media. 
When you want to protect your private life, you will not want to use social media, but even if you don't make use of social media, it does not mean that your life is completely private. As long as you have social gatherings, family, and friends, your private life has moved above being private. 

When you want to talk about the crypto community, those who choose to be on the private side and live free out of the control of others choose the decentralized technology. Why they can also live a totally different life on social media
There are just a few social media platforms out there that are decentralized and totally anonymous. That's why we still make use of Facebook, Twitter, and other social media platforms out there. On social media, they know what we want them to know about us. But on the blockchain, no one knows who is who or who owns whose wallet.

In conclusion, we care about decentralization because it's all about freedom. Anyone who wants freedom cares about decentralization.