It's because React (and other SPA technologies that also happen to work with SSR) is all the buzz. It doesn't actually necessarily make sense. The risk to a project is usually NOT the technology chosen for frontend.
Django templates are perfectly fine as long as you leverage template tags the way they were intended.
A hypertext approach such as HTMX in fact does give you server rendering, since you send to the client a normal SSR page with some extra annotations that add SPA features.
For React, SSR is secondary. For HTMX, it is primary.
Django templates are perfectly fine as long as you leverage template tags the way they were intended.