I'm bit confused there, you can get honorable discharge for that?
Yeah, you can, and typically US Army guys who "piss hot" (fail a drug test) get a general discharge under honorable conditions. And that's if they get discharged at all, it really depends on how bad the Army is hunting for people. From 2000 to 2009, for example, guys who failed a piss test got reduced in rank, lost a months pay, and did 45 days of extra duty/restriction, but they weren't automatically separated (kicked out). Marines were probably different, you'd have to ask USMCRET.
And, not to derail the thread, but the US mil has several categories of discharges, it aint just "honorable" and "dishonorable", 'cause we're cool like that:
Honorable : Guys that completed their time honorably, or were medically discharged. Or, homosexuals who were found out under DADT (don't ask, don't tell), 1998-2011. Or, dudes who were kicked out for being too fat/failing physical fitness tests. The best category of discharge; guys who g Cot this are eligible for all veterans benefits.
General discharge, under honorable conditions: these are almost always guys who failed drug tests/got DUI's. Occasionally, guys who went AWOL would get this type of discharge if they weren't otherwise a shit bag. Eligible for most benefits, but not the GI Bill. Can be appealed to honorable status after 6 months.
Other than honorable: Your run-of-the mill shitbirds; drug addicts, habitual drunk drivers, petty crooks and malcontents. This is the first category that can really hurt you in the civi world. Loss of most benefits.
BCD-- the "big chicken dinner"-- Bad Conduct Discharge: Can only be given in result of a Court Martial. Loss of all benefits.
Dishonorable Discharge: serious offenses (rapists, murderers, child molesters, and the like), the worst category. Loss of all bennys and now you're a convicted felon.