According to my friendly neighborhood AI there is no commonly accepted term for this effect, but when you have a community of people that is heavily selected for a particular characteristic you will end up with people that generally are outliers in some other significant ways too. In this case, caring deeply about email security is weird... unfortunately... and you can expect further weirdness from such people.

You can also read about people talking about this in the super-early computer user communities. When you had to be a bit crazy to even be interested in computers you ended up with people who were outliers in a lot of other ways too. As more people came in to the space it would regress to the mean... this is one of the things that "regression to the mean" can be regressing from.