It's unfortunate, but the prevailing opinion in Secure/Slaughter matches now is that they don't matter at all. It seems that the majority of the people queuing for it are brand new to PVP, just want to dip their toes in and check it out, and don't care about winning or strategy at all. The next most common are the PVP vets who came in via Roulette and don't want to wrangle cats to make their team even somewhat competitive. And finally you've got the PVP vets who came in via Roulette and immediately exit when they realize they didn't get into Seize.

I have had good Secure/Slaughter matches since Seize was introduced, but they are few and far between. It sucks, but it will remain like that until they stop making those modes a punishment for PVP veterans.