It's a disgrace that this has not been resolved since the original post/request was made over 6 months ago. It doesn't take that long to amend an app or put restrictions in place. Many parents have this same issue/fears over this.
I do not want my kids having anything to do with YouTube, like the original post, my 2 kids are currently fascinated by the same nonsense on YouTube but mainly a guy called FGTeev, his stuff is pure nonsense, mainly walk throughs of games, unsuitable kids games at that. I have had to delete YouTube from all mobile phones, and 2 iPads. I have also restricted their usage times on the iPads but now they have found the app on my Tivo boxes they are starting to use this. I need it gone swiftly. I cannot believe from carrying out a quick google search that i have found am that there is no means of at least parental control on this app, its appalling. This issue should have been resolved months ago or boxes provided minus the app at the very least. I will say it again Virgin are a shambles. I will definitely be leaving the service, no ifs no buts and this will be the deciding factor
As a father myself I do appreciate your concerns - I restrict my boys to the YouTube-Kids app on their tablets, but still catch my eldest watching the odd thing I'd rather he didn't from time to time.
As pointed out already there are other ways around this, and other means to restrict the content your children have access to - which may explain why this hasn't been addressed as soon as you would have liked. However rest assured your feedback will be passed on at the soonest opportunity.
I have restricted YouTube via all browsers even gone as far to set screen times on mobile devices. I'm not overly strict, i just don't want them watching rubbish, i am quite happy with them playing/watching educational & fun games, also when i was a child myself, i played games on various devices, ZX Spectrum, Commodore, Atari, Amiga, Mega Drive etc but games were not of the same ilk (Space Invaders, Chuckie Egg, Jet Set Willy, Alex the Kidd, Sonic the Hedgehog etc), now it's Granny, Hello Neighbor etc, the modern game is on a completely different level all together.
I Downloaded YouTube kids as well to mobile devices but there's nothing on it to draw them in shall we say and again the Tivo box does not have this option. Disappointing that we can't have a simple solution to block this.