The attitude that 'anime' only refers to animation produced in Japan is self-imposed. アニメーション never referred to native material only. And I think this has been discussed in great details here before, but anime is just an abbreviated form of 'animation' and can refer to productions from both east and west. The boundaries of the definition of animation have been kinda layed out by SS in
this thread. The 'CG' argument is therefore nonsense.
Indeed this is an example of oldschool hand-drawn animation technique, so it has every right to be included here ("VGMdb , the music of
visual arts and games"). And even more when looked at from a historial POV.