tataḥ mantradhyānasamayābhyupadeśāt tatkṛtādyathāvihitānuṣṭhānād āpnuvatāṃ śiṣyāṇāṃ paraṃ vyāmohanaṃ kṛtam ityatiśayoktiriyam
"Through it" [means] through the proper observance of what is prescribed in the teachings about mantras, meditations and observances; "a great delusion has been created for the disciples who obtain [these benefits]" - this is a hyperbolic statement.