This has been discussed a couple of times: "Removal of Mazda Connected Services integration" (270 points, 78 comments, 10 days ago)[0], "Mazda's DMCA takedown kills a hobbyist's smart car API tool" (83 points, 27 comments, 6 days ago)[1] - the first being the original blog post on Home Assistant, the second referencing that blog post, maybe adding more content and this article referencing both sources (but adding little)
[0]: >>37874220
[1]: >>37921584