TNA burned their bridge with ROH so many times. First with the Feinstein debacle, which was understandable. Then they started pulling talent from ROH just because they could to mess with them when they had a working agreement, so it is understandable that there are some sour grapes between the two companies.
It's also a bit interesting that despite TNA always seeing itself as WWE's competition, WWE seems to view ROH as it instead, at least since the move to national TV. Example being NXT running a PPV in the same city and on the same day as ROH is running their Field of Honor show.
It might not be the main factor, but I do believe it is at least part of it. ROH are bringing in Okada, Nakamura and the time splitters for this show. So the card is rather stacked. How stacked the NXT card will be can be a good inclinator to how they view ROH. On a positive note, ROH seems to take being noticed by WWE the right way, no potshots, just motivation to put on the best cards they can.