Shuffle my Music should do just that, shuffle my music...

I’ve seen quite a lot of topics on Shuffle my Music (SMM) but I don’t quite see my issue, hence this topic.

I’d like for SMM to look at all my music in my library and just shuffle that, i.e. RANDOMLY.  Now it resembles very much the Flow, playing songs I recentely listened to, and even suggesting new songs that are not in my library. Why? Shuffle is shuffle, isn’t it? Just pick songs from my library randomly regardless if I have never listened to them or a thousand times the last weeks.