It does abort the request from the front end’s perspective but the server will still process each of the admin-ajax.php calls. If you put in a debugger breakpoint at the end of the ‘get_choices’ method and then type in a several character search term, it will hit that break point for every character typed even though they were aborted from the browser.
Once the call to the server is initiated, xhr.abort() will only tell the browser to not wait for a response. The server will still process the initial request.
