The confusion, here, in my opinion, is one of whether the definition matches the intent.
MP, in and of itself, does not block LOS. Cover, in and of itself, does not block LOS.
If a SZ 2 model is behind Cover that would block LOS for a SZ 1 model, and choose to assume a minimized presence (MP), then the model may be considered to be behind Cover that blocks LOS. Note, however, that if LOS is blocked to this model, it is blocked from this model as well; in other words, if no model can shoot it, then it may not shoot at any other model. Common sense is, definitely, the key, here.
Please, let me know if this clarifies the issue.