Does SATOSHI NAKAMOTO really stated why he want to make bitcoin be in existence and did he specify they category of people that are going to per-take on bitcoin!!?
Many above users are pointed to suggest you to read the whitepaper, it's the answer because you will know about Bitcoin and you will the answer if you've understand about it. But for newbie I don't quite recommend to read the whitepaper because there's a lot of alien words where it would make you confused.
The first question is really simple, Satoshi only want to avoid third parties, while the second question, you just need to use your logic. If anyone can access Bitcoin through non custodial wallet and decentralized exchange, do you think there's no one can use Bitcoin?