In this case we'd need to relate it to normal asset/currency transactions. Is the rate of illegitimate transactions the same? 10X? 1000X? It can have several orders of magnitude more illegitimate activity while the statement 'the vast majority....' remains true.
Its more important that the US Deputy Treasury Secretary has intelligently differentiated between sanctionable centralized institutions and the network itself. A lot of people have talked themselves out of cryptocurrency by imagining that the [US] government would attack or outlaw the networks themselves, instead of acknowledging their legitimacy, and supported that with the imagination that the vast majority of use was illegitimate.
The only one who is moving goal posts is you, who have somehow setup this strawman that the collective position on HN was that the vast majority of crypto was illicit use.