I know exactly what you mean. I soak all dark purples, reds and blues in super hot water before I wash them.  I had a top I bought that had dark blues and Reds and was of a flimsy gauge type fabric.   This was after the third fresh water rinse.  I think it will be a hand wash item or in washer by itself or with other dark colors.

woah....is  any color going to be left???!!!

Strangely enough, yes, It's gauzy Red/White/Blue patriotic top and thankfully the white remained white.