Many SPA frameworks do provide state management. If you start from the idea that you want structured client-side state management for your webpages, you'll probably land on an "SPA framework". And if you're using such a framework, while I'll always advocate things like proper URLs and history (which the framework should handle for you), forcing a page reload when it's not needed seems pretty wasteful.
SPAs don't automatically provide any state management, and often the complexity requires even more work to manage forms. This is the complaint here, taking a simple requirement and forcing a webapp into it. It's completely unnecessary.