Why does the SPG permit sinful activities ?

Dear devotees,

Hare Krishna !

Please accept my humble obeisance. 
All glories to Srila Prabhupada ! 
All glories to our dearest spiritual master ! 

Excerpts from Srila Prabhupada's purport on SB 5.18.3 

Thus Sukadeva Goswami says, "How wonderful are these pastimes of material happiness transacted by the will of the Supreme Personality of Godhead!" In other words, materialistic persons want to commit all kinds of sinful activities, but without the sanction of the Supreme Personality of no one can do anything.  Why does the Supreme Personality of Godhead permit sinful activities? The Supreme Lord does not want any living being to act sinfully, and He begs him through his good conscience to refrain from sin. But when someone insists upon acting sinfully, the Supreme Lord gives him the sanction to act at his own risk (mattah smrtir jnanam apohanam ca [Bg. 15.15]). No one can do anything without the sanction of the Lord, but He is so kind that when the conditioned soul persists in doing something, the Lord permits the individual soul to act at his own risk.

Your servant,
Gomathi Ganga DD