Mr Reeners posted on the STCC Facebook page and it looks like he really hasn't done his homework.
These 'rocks' are actually called 'RIP-RAP' by folks like FEMA, NYDEC, USACE and ASDSO. They have been used since time began (for dams and canal embankments). They are there to protect the embankment from erosion by wave action, wake from boats etc.
To say they knew more long ago, just shows Mr Reeners hasn't studied the subject at all. It's typical of many members of the STCC.

Here's your homework Mr Reeners.

https://damsafety.org/dam-owners/upstream-slope-protection