Back when the GAF bubble popped and ERA was made, once the GAF bubble reformed there were a lot of disgruntled ex-ERA members who ended up either leaving there or being banned then coming back to GAF and bringing that disdain for ERA with them, even when myself and others kept asking for them to let them go and make GAF better and worry only about GAF instead of moving with spite.
It didn't work. People are spiteful, vengeful, and hold grudges. People also hatewatch and mostly interact with things they hate, nearly on a daily basis online. It simply is the way of things.
Just make sure you don't get too caught up in the 'our team is better than their team' rhetoric. It is just team sports at the end of the day.