Well unless they managed to capture 2 Hecate's as i think i saw in the wiki (not sure though) they must of produced something.
Alright, you're going to have to post a link to this. I just can't remember in any tech room description, briefing, or other canon information that confirms two Hecates being captured by the NTF. Every single NTF destroyer encountered in the main campaign, including those that played roles best filled by Hecates, was an Orion. If the NTF had been producing Hecates at all, then why weren't they deployed to Epsilon Pegasi, Deneb, or Alpha Centauri, where their 150 strikecraft could have turned the tide in favor of the NTF?
Also lets not forget that the NTF actualy fought and ofensive war at one time so you have aditional casualties there.
Yes, but it also was a surprise attack on the GTVA. There was virtually no resistance in Polaris, as it was his fleet stationed in the system that he broke away with. The attack on Regulus was very likely a surprise attack, and those that didn't defect right from the get-go were likely forced to surrender seeing the size of the fleet against them. The remainder of the fleet in Regulus likely retreated to Sirius because of the overwhelming NTF forces, leaving Sirius as the only system one of the three that could have mounted a counterattack.
Of course, then take into account the NTF sympathizers in Sirius, and the combined strength of two fleets bearing down on one system, Sirius very likely didn't last very long either. When the NTF was forced to engage in three different border systems, the offensive likely scaled down.
Also bear in mind that NTF officers and strategists weren't exactly stupid either: any commander that can organize a blitzkrieg attack that destroys 75% of an enemy's forces in one system and provide fierce resistance for a two-pronged attack on another front must have something more than luck working for him.