That sounds like something I said but if so, it's not an accurate quote. Many newcomers assume an IBM thing must be electronic, but it makes a big difference in typewriters, so I try to clarify things. And I do so by pointing out that most Selectrics, the common ones, the early ones, the office ones, are mechanical, and only some of the later developments for relatively unusual applications have some or a lot of electronics. Not the ones we are finding at yard sales and will have to work on or "repair".
But let's not get into a discussion of which ones are which. Although the proportion of mechanical to electronic that were produced over the whole life of the Selectric line would be interesting to know.