However, if this is an investigation of individuals, the Fourth doesn't apply because they're not searching the individual's effects. If it's an investigation of the exchange, then it isn't a general warrant.
The quotes from the investigators said they were wanting to see if any of the exchange users were using it to evade taxes. That's an investigation of the individuals. They did not say they were investigating the exchange because they had probable cause to believe the exchange was evading taxes. They have no specific probable cause to search the private financial data (papers and effects) of the individuals. It's a fishing expedition using a general warrant. That's the reality.
Of course, a Venn diagram of reality and the US legal system would show only a very modest area of intersection, particularly in more recent times.