All companies have blackout periods around disclosure of news and financials.

POET always claimed to have years long blackouts but these were conveniently dropped whenever someone *coughtthegooddoccough* wanted to sell. 

I would suggest the "blackout periods" were just window dressing to make the "Why isn't management buying? question easier to answer.

Ultimately, it is not a requirement for management to buy and their personal investments are none of our business.

If you want a good simple reason for them to not buy, how about not putting all their eggs in one basket.

Diversify - an odd concept for this board but a good practice.