I also worked in "data processing" 35-40 years ago. Have maintained contacts and peripherally worked with it as it evolved to IT, and as programs evolved to application programs, and after the iPhone, to apps. Let's face it, "security" 35-40 years ago meant locking up the mainframe in a fort or a fortified basement (or, in one place I worked, the computer was on the top floor and only those with keycards could reach it). There was no internet. Networks, if they existed, were slow (1200 bps or less, usually), used phone lines, and usually were for connecting terminals to mainframes, not computers to each other, with very rare exceptions run by or for the military or very large corporations. Data i/o for ordinary users frequently consisted of shipping boxes of punch cards or tapes to data centers, and getting boxes of printouts and tapes back.

Remember the old line: never underestimate the bandwidth of a station wagon full of tapes? The latency sucked, but then so did dialup phone connections.

Things have changed, Mr. Scaryman. A certain amount of paranoia about the internet is healthy these days. Reasonable technical measures and usage practices are necessary.