McCoy certainly started it, but Umenyiora has continued responding to whatever reporters will listen. First it was the NY Times, now it's the Newark Star Ledger. He described their relationship very succinctly.
"Yeah, me and him, we had words on the field - both times we played. I hate him, he hates me, period. He chose to take that off the field and make it public when it's something that's between me and him. It's something we can address on the football field. He let the whole world know about it, so I'm going to respond."
So they're not friends and apparently never have been.