Since gaming now lives at http://YouTube.com/gaming , the old Gaming app is going away on May 30th! If you were subscribed to channels in the Gaming app, they’ll automatically move to your YouTube subs feed on May 14th. More need-to-know info→ https://yt.be/help/yRe4
Anyone can file a counter-notification just by giving all their information, and unless you actually provide YouTube with a copy of a lawsuit then they will reinstate the videos. I can't afford to spend thousands of pounds/dollars on attorney fees