As a frontend dev I give him the first point, API versioning, but none of the other. For example:
2. Validation
> With Spring MVC, you add the validation annotations on the Java code and Thymeleaf can display them when something is wrong.
In the same way the backend can respond with the problems in a 4xx
3. Security
> [In SSR], it is for instance trivial to not render a ‘delete’ button if the user is not an administrator.
Conditionally rendering a delete button has nothing to do with security.
4. Secured file downloads
> With a SSR application, you can have a normal <a href=".."/> and the security aspect is handled on the server via the session.
An SPA can have normal links as well. But the main problem here is implying that you can handle that security on the client.
---
SSR for CRUD apps is fine, but this article critiquing SPAs with innacurate examples, and in cases equating them with bloated tech.