there are various definitions of "racist" and it is not always clear what posters mean.
it is also not clear if this racism is or can be related to the person's employer (eg they have all their work details on their bio, etc)
Nobody is defending racism. people are defending anonymous snitching that may have serious real world consequences out of all proportion to the crime.
And to do so anonymously? is underhand and cowardly. If i encountered someone on my fb friends list who made a racist comment, i would: challenge them by replying to the comment.
Probably by unfriending, and maybe even blocking them.
I may, if they have all their employers details on their profile, warn them that what they have written is racist and someone else - not me - may alert their employer.
The ball is then in their court.
If it was someone i worked with? I would just go up to them and tell them that they need to be much more careful about posting racist tripe, and unfriend/block.
I would also be checking the company SM policies.
But i absolutely do not believe that anonymous reporting is a good thing in these circumstances.