Yes I'm quite sure that's the official Pokemon Database account, because all of those videos have been featured on our front page.
Such as "Video of new Pokemon English names". On that page we can see that it links to this video from the Pokemon DB youtube account, which pretty much confirms it. I can't imagine that PM would feature videos from a channel with that name if it wasn't his own.
Edit: That particular post also says "I'm hoping to create some more videos in the future, so you can subscribe to our new YouTube channel, "PokemonDbNet" to keep updated." with a link to the previously mentioned youtube account.