I think it’s not that software engineers aren’t engineers; but more that they’re most equivalent to combat engineers — engineers operating under time-pressure and shipping-pressure, where the systems they build need to “work” (in the sense of a bridge getting people across a ravine) but may only need to work once; and where it may be perfectly fine/expected/required to need to “baby” the resulting engineered system along (i.e. letting a batch of people over the bridge, then closing it to traffic, examining the piles for faults, and shoring up the ones that are slipping; then reopening the bridge, in a cycle.)

It’s not that this type of engineering is “not engineering”; it’s that it’s engineering where the engineer themselves (and their ability to actively re-stabilize the system) is considered a load-bearing element in the design, such that the system will very likely fall apart once that element is removed.

Combat engineering is still engineering, in the sense that there are still tolerances to be achieved, and it’s still a disaster if the bridge falls over while it’s in active use for the mission it was built for. It’s just not considered a problem if it falls over later, once that mission is accomplished.