If the specific question is:

Why was this scholar not cited?

then possible explanations include:

lack of merit,

lack of visibility,

disciplinary isolation,

language barriers,

intellectual fashion,

institutional exclusion,

ideological bias,

deliberate suppression.

Therefore:

Lack of citation does not prove lack of merit.

And equally:

Lack of citation does not prove suppression.

Both statements are logically symmetrical.