And what is software engineering but exactly that dynamic? Relational algebra and distributed systems design are most certainly based on applied mathematics, and one uses tooling built around the underlying theorems to ensure that parts mesh together in a reliable way that scales under load. Some engineers take their learnings from specific projects and write papers, and that's amazing, but that doesn't mean that if you don't have an Arxiv account you're not an engineer.
We're not just fire-and-forget script writers; we're engineers and we draw on decades of an industry's worth of deep knowledge to ensure our systems are rock-solid. I hope everyone who considers themselves "just a software developer" finds a team that appreciates this.
Whether math is being applied doesn't seem like an important distinction to whether something is composition or not. I reason about computational complexity when I build distributed systems, just like civil engineers reason about tolerances. But I'm still assuming a best-of-class sorting algorithm and a reduction of some domain problem into a shortest-path algorithm. The same they do about I-beams and spans.