You've selected an awful example. The one you choose wasn't an argument on anything technical concerning bitcoin, nor was it a claim on possibility of centraliz

You've selected an awful example. The one you choose wasn't an argument on anything technical concerning bitcoin, nor was it a claim on possibility of centralized exchanges blocking on chain transaction. It is like you haven't read the preceding and the following paragraphs. Author was simply relying his/her experience in discussing with crypto supporters. In the paragraph you quoted the response of crypto supporters is that exchanges have no power. In the following paragraph the response of crypto supporters is that exchanges have the power.