generally pitching Fury against Eagle has as much sense as pitching a Conquest against an Onslaught. Though admittedly Conquest is underpowered compared to the Onslaught.
Before the missile nerfs the fight between the three tech capitals was in general regardless of build Onslaught < Conquest < Odyssey < Onslaught. After it pretty much is Onslaught is better than the other two due to it shooting down any Squalls thrown at it. Squall without officer support got over nerfed in the HP department. Functionally half of the Conquests total firepower is in missiles and large missiles are in general fairly weak for their cost ATM when facing heavy PD. So, it's really not that the Onslaught is OP, it's that sim Onslaught hard counters large missile ships whereas it didn't use to.
Sim Eagle uses a terrible stalling build and absolutely should not be winning so decisively against a ship it can't escape from.
The logic is that Fury is meant to dilute the battlefield by roaming and choosing its engagements wisely. Utilising its extreme mobility of more than 130 units (possibly, which can be further easily augmented) to kill all the weaker support units of carriers, frigates, destroyers etc. To then leave the major core exposed to ridiculous damage.
...What? It has a top speed of 95. It also can't dilute the battlefield as it costs 20 DP. If you want to dilute the battlefield with cruisers that punch down, the only option is the Falcon.
Eagle on the other hand is an elite duellist. It's designed around bullying a singular target. You can put it against a Dominator and often neither will win in spite of Dominator also being powerful against a single big target. Eagle is just a master of kiting and retreating.
Unless the Eagle gets overloaded, which every Dominator build can do if it has adequate kinetic damage, and three Typhoons. Also, the Eagle has maneuvering thrusters, so it can handle decently large volumes of small ships assuming it has Phase Lance.
Fury ironically enough has really high durability of like 20k shields or way above that... And with a proper build it can win by attrition thanks to the utility of EMP.
It has a base shielding of 9,000 at 0.7 efficiency for an effective shielding of 12,857 and 1/7. Which is less than the Eagle's at 11,000 at .8 for 13,750. Did you accidently mod core files?
At max caps without bonus hullmods or skills (30 caps) you get an extra 6,000 shielding, meaning the Fury and Eagle have nearly the same shielding at 21,428 + 1/1.75 and 21,250. For reference the Apogee, a functional combat freighter at 60 speed, has a shielding of 25,714 + 1/3.5 if given max caps.