From my view, the intrusive inclusion (i.e. Integrating content directly into game client and by extension, the game) of Arpeggio of Blue Steel into the game was the final straw that rekindle the anime hate already existing in the NA cluster's forums. That may be an overstatement, but it did wake that sentiment up after quieting down for some time. The content being here to stay means that the divide have become more real than before and it will be here to stay also. Well, it's NA cluster we are talking about, and NA means that intolerance of anime is strong.
'Opting out' means that one is excluded from the event. I do not know why they cannot just exclude rewarding of ships outside of Yokosuka port or just silently reward it (my guess being, it has to do with the ships and crews not existing outside of Yokosuka port), or make parallels, sans the ship.
I wouldn't hope for a decent discussion at that place anymore on the topic, the pro-ARPs will just tell me to pretend I never see them and not to go to Yokosuka. Hell, I believe I can reskin Yokosuka, return the ARP ships to normalcy, silence Iona, change the mental model's faces, and even change their names...it doesn't change the fact that not using Yokosuka exclude one from the other, usable rewards, and I doubt that many people have the guts, the know-how, and/or the resource to change that many things to make things bearable.
Alas, I think it's a uniquely NA thing...and I don't think the opposition will let it go, even if they cannot do anything about it.