Loss of Gravity

Disclaimer: This text was NOT written by freakingcat. It came from an anonymous source.

Suthikiart Jirathiwat and Pracha Maleenont are quite close to Thaksin Shinawatra. They are still on good terms. If the reds set the blaze it would not make sense at all.
Places burnt down are symbolic of regime/system and representation of success. However the perpetrators are sparing many business locations
Dusit, MBK, ASTV, Nation, SisaoTewes, Pullman Kingpower, all left untouched. 
Those would've been the reds' targets. Remember who was feuding with Central and BEC before all of this? Who was the biggest enemy of the Central Group and Ch. 3 in the past 3 years? The direct beneficiary of the fire is not reds or Thaksin...it's the man who feuded.
The fire kills 5 birds with one stone: Channel 3, Central, Thaksin, Reds, Anti-Monarchists. Pongpat was used. Game over for Thaksin as he and reds are delegitimized, while opponents of Central/Bangkok Bank/BEC benefit. Think about this for a minute and you'll realise the missing jigsaw of this puzzle. 
The men behind the blaze are the men who wanted to drive BEC/Central/BBL out of business and blame it on protestors. The fires irrevocably end the reds shirts movement for now, while Thaksin cannot conceivably ever return to politics or even to Thai soil.
The victims of the fire are not Thaksin/Reds's enemies. They are the enemies of Thaksin's enemies. Ultra-hardcore-right-winged conservative types stand to benefit from this chaos.
Watch the aftermath closely and you'll see. Those who are desperate about clinging on to power are required to create an element of fear in the heart of its population. The incentive is greater than those who are aspiring to attain power.
People will go to great lengths to protect remaining interests while the threat is eliminated to foster a rally-round-the-regime type of feeling.

The goal of the movement to eliminate Thaksin forever from the system was not accomplished until today. It is end-game for him. We lose. Regime wins. 
May I stress not coincidence ASTV, Nation, PullmanKingPower, Dusit remain untouched. This battle is deeper than what meets the eyes. And SiSao is untouched.