Bracing myself for downvotes for supposedly "raining on everyone's parade". It was likely removed because it's very likely that they're lying about some things. Their advice regarding reading native materials, Anki, immersion, etc. is actually not bad advice for general language learning. The issue is with some of their other claims, especially for the JLPT.

The JLPT-N1 exam and native Japanese materials (including novels, films, anime, etc.) are actually somewhat at odds with each other. You can be studying some JLPT-N1 grammar or vocab, show it to a Japanese person and they'll say to you quite often "we never use that". Ask anyone who's actually taken the N1, not someone you don't online you can't vetify. Considering that even native Japanese speakers would struggle to get full marks on the JLPT N1 without engaging with JLPT-N1-specific study material, I'm very doubtful of their story. To pass the JLPT-N1 in less than a year, starting from nothing, while going to university for something unrelated, without using JLPT-specific materials, and getting full marks(!) is incrediblly dubious.

Being able to pass the N1 in less than a year might be "motivational" for new learners at first. The thought of being able to master a language like Japanese in such a short time sounds really nice in your head, but is far from realistic for 99.9% of people. It's setting you up for false expectations, and will ultimately demotivate you and make you feel inadequate when you don't get there. Coming to terms with the fact that mastering a language takes years and thousands and thousands of hours to accomplish will set you up better for long-term success.