Because these phones don't have Knox security. To use Secure Folder Knox security is must, Knox is a both hardware and software based security. Most of those M series devices that you're talking about don't have hardware level Knox.
Yah, but at least they can make a secure folder like application for this type of ranges because we also need privacy for our media and if this will be provided by the brand of the same phone then it feels more safe than any other developer's application.
Provide feedback to samsung developers via feedback section(ask questions section), they need a minimum no. Of feedback from unique users (respect to no. of sales of device across all platforms), to add a premium feature. To provide feedback in samsung members app, Open Samsung Members Application > Get help > Send Feedback > Ask questions. If you want quicker action, write on every channel, whatsapp, samsung members app - ask question and error report, ceo escalation desk, service head desk, call toll free no. , support email of samsung, youtube, samsung content help( google it),samsung live chat,twitter, instagram,facebook,linkedin,etc. It is the power of our feedbacks only , that samsung started to give clipboard in many devices.
