I cannot disagree more vehemently with the bolded text. For centuries, black people have been told they have to suck it up when they are beaten, killed, or demoralized by white people. Black people are told to be the "better person". Having Iris, who was Cait/KF's victim, be the one to pursure friendship, give them a blanket pardon, and then reward Cait/KF was just another version of the "noble savage" and the "mammie" tropes. No, I cannot agree that Iris was the best choice. It would have made more sense for Cait's best friend, Cisco, to do this instead.
In the end, what Iris did only served Cait/KF. Iris got zero benefit from it. It made Cait a key member of the West-Allen wedding. This friendship only lasted long enough for the black woman to be used to essentially whitewash the white woman's sins and crimes. Only at Barry's trial, after DeVoe framed Barry, did we see Cait and Iris kinda holding hands very, very briefly. When Iris was dreading the impending "death" of Barry in Crisis, not once did Cait or Killer Frost comfort Iris or ask Iris how she was dealing with this.
As for Barry, he knew Cait had worked for Amunet in human trafficking when he told Cait, "you're a good person". So, Barry did vouch for Cait, too.