Because trading is not a crime, and this so-called "regulation" criminalizes trade.  If you and I agree to exchange bitcoin for dollars, that is not a crime. There is no victim. We have a right to voluntarily exchange our property.

If, on the other hand, you steal my bitcoins or my dollars (or otherwise obtain them fraudulently), then that is a crime - an actual crime with a real flesh-and-blood victim and actual provable damages. There are LAWS against crimes like THEFT and FRAUD. There have been since...forever. Those laws are essentially just. It would be nice if they were properly enforced.

Please note that the existence of laws against theft and fraud do not magically stop people from committing such crimes. Likewise please note that criminalizing trade through "regulation" does not magically stop people from committing crimes either, but it does introduce something new into the picture - the punishment of provably innocent parties, and the intentional distortion of markets by government and corporate forces bent on power and control.

If we want to see some measure of justice, we should advocate that laws against theft and fraud be properly enforced, not that innocent people be punished for non-crimes or that certain groups be given control over markets other than the people who voluntarily participate in them.