You have yet to provide any evidence for this claim.
Answer me this-Since alcohol is legal and there are millions of americans who use it responsibly,would you also assert there are millions of americans who could use crack responsibly?
Responsible cocaine users would no more use the crack form than responsible drinkers drink straight Everclear. It's the illegality of (some) drugs that has encouraged their increased potency---just as Prohibition turned drinkers from beer and wine to liquor.
"You've provided no facts or logic to support your position; I've provided facts and logic to support my position. Advantage, me."
Don't need to provide facts on this one-common sense tells me it's true.
Ah, the anti-drug-freedom position in a nutshell: 'My mind's made up, don't confuse me with the facts.'