My phone is AOS 5. It auto-detects captive portals and auto launches the browser. From there, just like there are countless ways to fuck up a webpage, there are countless ways to fuckup a captive portal webpage.

Web developers are profoundly incompetent on a widespread scale. I think a lot of it is done by kids who just want to play with the latest HTML frills and latest JavaScript constructs. These are not well-trained professionals who understand the problem of rapidly changing “standards”. They are not taught about backwards and forwards compatibility, and that the latest language frills should be avoided (or guarded by conditionals based on user agent strings). These same undisciplined hackers are apparently writing captive portals.