I was a bit curious:-

"They" tell us that:-
1. The sorting machine can't "see" the black so it gets missed at recycling.
2. Soft plastic is, currently, not recyclable.
I have seen those HUGE bales wrapped in a few different colours now; but "once up a time" they were almost all black.

Jerra dropped a sack of leaves for me to add to my growing leaf-mould supply.  It was in a sack which boasted it was made "with" (not from) 
"UK WASTE FARM PLASTICS" many of which stand a chance of being invisible to the sorting software being made of soft plastic.

I wonder why "we" can't recycle soft/black plastic?

I forgot to mention a degree of "colour-blindness"; this "Green sack" looks awfully black to me.
;¬)