“I’m going to create three different sock puppet accounts and join a leftist group and lie in wait for a year and a half and then one morning write a hundred shitty comments about black people!”
And if their shit is up for 3 or 4 days, that might be enough for them... I do not know how much attention a hundred comments create in the "suggestion system" of Facebook.
Maybe it was hacked accounts and they just got hacked? Also often spammers etc create thousands of accounts and let them sit a bit, because accounts a day old are always automatically under suspicion. Maybe it's a defense against automatic detection.