Easy one — Engineers have technical ability and they tend to be focused and (somewhat) single minded. You are probably also more detacted from people than, say, a marketing major. If you are able to get an engineering degree, you have a demonstrated ability to finish what you start.
Engineers are trained and probably preconditioned to focus on data that they can lay out on a table and work with - not the peripheral "noise" that other people might bring into consideration.
They also tend to over evaluate their own field of work and over simplify things outside of their realm. (I had a very respected associate once who ran for public office - couldn't fathom why people laughed at his campaign speeches because they were all so rational to him)
Conversely, today's engineering grads have been taught to trust computer programs written by others who are themselves programmers - it is often pointless to ask for confirmation of a finding because no one agrees on how the thing works and no one can do it on paper.
None of those attributes are "bad" but neither do they help in dealing with the less objective world; where it may be easiest to go for the absolutism that terrorists and socialism/fascism require.