I think we all know that Mike is an emotional person, and let's not forget that he really loved DT and didn't really want to leave.
It is expected that he shows some negativity seing DT continue as strong as ever without him, because he wanted a hiatus, not to leave.
But it is very possible that these "likes" on FB are just careless actions, as i guess he liked the parts that talked about Adrenaline Mob and how he is irreplacable. And to a degree, he is.
His role in DT was very important and leading, and i'm sure it is painful to him seeing the band being happy carrying on with another drummer. I don't justify his actions, as they seem a bit immature to me, but i can understand his feelings. But he has to move on, if he hasn't already.
I'm sure time will heal the relationship between MP and DT, and we as fans will continue to enjoy great music from both sides.