You 100% shouldn't enable a cheater, but there is merit in that we don't get to control how we feel. Here she's trying to forget her feelings in a pretty unhealthy way by rebounding on the first guy that was nice to her whom she doesn't even really like like that. She's not confronting her emotions well. And that doesn't mean getting back with the cheater, but stuff like letting herself feel sad over it or be angry at him. I like the line love him until you hate him because it feels like validating her emotions. A lot of times we forget that because we're dealing with fiction and we think shipping wars or someone should just get over a trash partner. But in reality we're kinda awful in love. We can often fall for the wrong people and it takes a long time to pick up those pieces because we can't just tell our brain to stop caring about xyz.
That said I could be completely off the mark and bexause of Machida's advice she gets back with a terrible cheating boyfriend and has a miserable life.