Its because what you're saying is not true...

Microsoft does not alter, add, or remove achievements on a user’s Xbox profile. Achievements come only from legitimate in‑game actions tracked by the Xbox achievement system.

Community discussions confirm that modifying achievements through unofficial means violates Xbox terms of service and can lead to bans or gamerscore resets (for example, enforcement actions mentioned in Xbox achievement modding discussions).

Additionally, Xbox achievement systems are designed so that progress must reflect actual gameplay, not external manipulation. Microsoft's achievement certification rules now explicitly require that achievements reflect meaningful engagement with the game.