Not sure I fully understand this issue. Logging a topic in the Site Feedback area to explore.
I am under the impression that you can use the browser’s back button to go out of a topic, but maybe I’m missing something or maybe this doesn’t work with screen readers?
Some websites have recommended to me not to use the back button, as it could confuse things on how websites are cashed or when posting a topic. For example, might take me back to the post screen, instead of the main screen. Novice users might just be getting to groups of finding their way around the forum, and want to get back to the screen they were at before entering the topic I want to browse. Also, having a back button for each topic, confirms that no issues will occur using this method, rather than using the back button in the browser.