- people who agree we are heading into a bubble (altought different views on when it will burst)
Unfortunately, people who can't and don't want to understand Bitcoin started to invest in it. They want to earn easy money without doing much. I wouldn't be surprised if they blamed Bitcoin for their loss if it crashed.
- people who agree that miners are increasing transaction costs dramatically and are a threat to very idea of decentralized Bitcoin itself
I have to partially agree. SegWit helped us to lower transaction fees but due to increasing value of Bitcoin, the transactions are getting more and more expensive.
- people who have lost money due to various hacking scams
It's not our fault that they can't follow simple rules especially if they have a lot of money in Bitcoin. There are many guides on Bitcointalk which tell you how to behave if you don't have a hardware wallet.