The fact that you frankly acknowledged the drawbacks and foolishness of casual cocaine use, with the benefit of additional age/maturity/experience, reflecting upon your own actions as a younger person is probably why they cleared you.
Additionally they were looking for any hint that you might have had an ongoing/current drug habit where you would either be vulnerable to financial pressure or societal coercion from drug dealers/persons associated with drug dealers, and that they they believed you were no longer a user was likely a factor.
Additionally they were looking for any hint that you might have had an ongoing/current drug habit where you would either be vulnerable to financial pressure or societal coercion from drug dealers/persons associated with drug dealers, and that they they believed you were no longer a user was likely a factor.