Calder did nothing wrong. It was all about exploiting a weak point. The Tevs overextended and were in the process of giving up Neptune, relocating their force to Jupiter AFAIK.
If Calder would have faced Steele at Neptune, the Tevs would have lost the Station and tens of thousands of GTVA personnel, as well as medical ships and fleet tankers, although I think he would've left only the personell behind, enacting General Order Seventeen: destroying the Neptune base and everyone aboard in order to prevent its capture.
The weak point was Lopez, because she showed compassion and after the mauling of her battlegroup, she was unwilling to sacrifice more.
Calder went all in with Vikrant, Toreador, Serenity, Segura, Tripoli, Wolfach and Glaurus engaging the Carthage and its screen. The Wolfach withdrew and the Glaurus went down with all hands. If memory serves right, the Segura and Tripoli were gone and the Serenety disengaging. Calder actually depended on the Fedayeen for winning this for him.
Netreba pinned down the offbalanced Tev forces and Steele could and would not send help, unwilling to engage in a decisive fleet battle.
While Calder hoped a victory would hurt the Tevs, quite the opposite happened...
But he was not decieved, he was rather willing to go for it, but was informed at the same time. He did not trust the Fedayeen, but Laporte, hence she was in command.
Edit as for fleet assets: If we assume that the Masyaf, which is on first fleet deterrence assignment, this would leave the Shiraz, a Karuna which is deterence also, so there is a possibility that she is Fedayeen too.