The vast majority of people on Steemit are awesome but occasionally you can encounter one who isn't.

The reason they get away with it for a while is because if we start flagging them we will be just like them.

But you are now just at the point of having full backup - if any of your posts ever get flagged from now on your followers will back you up and this spineless weasel will probably stick to harassing people who don't have backup.

Quality content wins over time and you have that - sooner or later this guy is going to piss off the wrong person and learn what an angry whale can do to his reputation!