I’m not saying this is correct, and it’s been a long time since I went through the fundamentals so not sure what is taught , but I just replicated the A minor pentatonic like you are doing and yes I am touching the 5th string each time. Which mutes it. 
But, it sounds fine because my notes are clean when I play the scale. 

In fact I’m touching a lot of strings, but again, the notes that are supposed to be clean are.