The problems with so many of these issuers and the DTC is definitely convertible debentures and debt. The current trend is fabricating old debt and settling it with fresh shares, often at a very inflated price.
As an example, GRCV, which was perhaps the most obvious pump and dump ever when it was Crowne Ventures, did a 1 for 10,000 reverse split back in November. In February 2013, they settled what they claimed was $25,000 in debt (although the prior pump and dump was fueled by fabricated debt, and since they are not registered with the SEC and their financial statements "filed" with OTCMarkets are questionable, at best, who knows if that $25K debt was real) with the issuance of 25,000,000 shares. The stock at that time was selling for $2 a share. On paper, they settled $25K of debt with $50 MILLION in stock. Granted, they couldn't dump that much stock at $2 a share, but they were able to dump quite a bit of it at an average price of around 5-10 cents or so. Not a bad return off of $25K which may or may not have actually been "loaned" to the Company.
Blaming the DTC for enforcing the laws and regulations is like blaming the police for causing mayhem by responding to a murder scene. The crime was already committed before the DTC takes action.