They, centralized exchanges, can create their Decentralized exchanges. You can use their DEX or refuse to use their DEX but with different reasons to accept their DEX product or worry about it and don't use it.

Is it a good platform that is decentralized if it is built up by a centralized team with many members like founders, core members, compliance and marketing team members are known by governments and the public?

It is not good and if you think their DEX is actually decentralized, you have to correct your thinking. A true decentralized exchange must be built by an anonymous team to help it can not be shut down by arresting a founder or a core team member.