[ubertaco]

More broadly, it sounds to me like the general principle is "are you engaging in some activity which is a shameful secret for you, and which could thus be used to gain leverage over you by threatening to expose that secret?"

Part of the problem is that it sounds like there were baked-in "hard-checks" about things that were automatically assumed to be shameful secrets that could be used for leverage.

[myrandomcomment]

It comes down to never lie about anything when you are being interviewed for a clearance. They will always find out. If you hide things, then you could be blackmailed as you where unwilling to admit to them in the interview. Yes, there where hard checks based on social normals at the time. Being gay used to be an issue, as wrong as that was. But at the same time, drugs, being a drunk, hitting your wife (prone to violence) etc. were also items on the list. Anything that could cause public embarrassment that you could sell out to avoid.