I believe the same is true with certain drug use. For example, on form 4473 you are disqualified, at least for a period, if you are "an unlawful user of, or addicted to, marijuana or any depressant, stimulant, narcotic drug, or any other controlled substance". Small use of many of these drugs is a misdemeanor, and this doesn't even require a conviction, just a self admission. In addition, the term "user" is undefined and very vague. Does this include a person who takes a puff or pill once a month, or once a year, or ever in your life? At what point are you no longer a "user". Does taking a drink once a month make you a "drinker", or having a cigarette once a year make you a "smoker"?
Taking away or seriously restricting constitutional rights is a serious matter and deserves clear guidelines that we can all understand.
Tom