"CS is the welding. SE is the structural engineering."

No. Computer Science (CS) is the basis. It's the fundamentals underneath Software Engineering (SE).

The author is trying to convey that current CS education is not enough to create a good Software Engineer, which is true. But SE is a specialization and CS is a broad overview of the core components of a computing education.

If you want to create a comparison to Civil Engineering (CE), this isn't it. CS to SE is more like the underlying physics that support the specifics of Structural Engineering.

A more apt comparison is that the low-level programmer who takes a spec and just implements it is the "welding"; this would be that fresh hire out of college in their first position.