To put some links and sources to that.
The specific definition we use to determine "Anime" is "An animated series, produce and aired in Japan, intended for a Japanese audience".
This is a music video by an artist that contracted out a studio that happens to also produce anime. If A-1 was contracted to product episodes of spongebob, we wouldn't allow that here either.
So let's see what the checklist is.
- Animated Series
- Produced and aired in Japan
- Intended for a Japanese Audience.
And this video fulfills every single one of those checklists.
It is also in the style of most traditional anime, but since the rules of the subreddit don't consider style to be a denominator of anime, I'll avoid talking about that.
Simply put, by the definition of the subs rules, this is clearly anime. People don't make videos in Japanese if your intended audience is western, you do it because your target audience is Japanese. Just because they simulcast the video with subtitles over the internet at the same time of the Japanese release, does not make it intended for the western release.
And that makes it pretty different from Spongebob.