I agree. I was not surprised that President Obama waded in on the British EU exit referendum. This issue is not of much importance to US citizens, but it is very important to the one world government movement. Off topic, but: I find it sad but amusing when my friends argue about democrats vs. republicans; both parties serve their 'people', the corporations.
I was surprised because it goes against the principle of divide et impera. Apparently a divided Europe makes it easier for the USA and China to do whatever they want, and Russia too. Unless the EU with a skeptical UK is worse off than without it.
But I see your point. It's not American interests against European ones. It's to prevent a secession in a geographical space more and more dominated by some corporations and financial institutions. A secession would make it a little bit harder for them, but not so much IMHO, unless it spreads and the EU shatters (maybe because of the migrants crisis.)