That is a weak justification, commonly used by criminals. A liar might say, 'everyone lies'; honest people don't say it. Unless we are engaging in a very philsophical discussion (possible on HN), we don't need to explain the problem in detail.
It's not a "justification" of anything, just a question for someone who blames other people industry as fraud. Just curious about way of thinking, nothing else.
And everyone lies indeed, those who deny it are either delusional or liars. It's human nature.
I didn’t blame an industry as fraud. GP was describing a specific fraud that occurred in an industry. Not the same. I’m sure there are legitimate crypto businesses.