Maybe interest wasn't the right word, I'd like to think most fans would be interested in any game of RL. The OP seemed to be suggesting that he was expected to support England though, which doesn't make any sense considering he's not from there.
Why would you be more inclined to attend GB matches than Wales matches?

I wouldn't be, nor have been. I would go to both, but I'm not so keen on going to England games. I am Welsh and British, not English

Absolutely

I have no problem with people saying that they are not interested in the internationals game (I have a real problem with people deriding it though). If somebody said “I am interested in my club and that is all” then that’s fair enough I would respect their view and move on. But that same individual then cannot moan about the lack of coverage the sport gets in comparison to its peers as internationals are singularly the best way to raise the profile of the sport – a profile that all clubs at all levels of the game would benefit from

It is not a change in policy or action that will build a flourishing international sport, it is a change in attitude

A good and fair post.