You are evidently a mindless idiot who can't even grasp the most basic english sentence, or whose mind is unable to grasp concepts a 3-year old would get instantly.And why it can't blow it up after that? From what I remember from both novelization and movie, Rebels flew inside Death Star throught same vent that destroyed DSI (OK, this one was several times wider).
I repeatedly told you that that "shaft" was there because the second Death Star was UNFINISHED. The design of the second Death Star specifically REMOVED that heat vent and replaced it with millions of millimeter-wide vents which would not cause such a catastrophic failure.
That is evident when watching the movie as well - the Rebels had to attack because it was their only chance, they expected the DS II to be not functional, the Emperor (supposedly, it was a ruse) visited because it was not finished yet and he wanted to oversee the rest of the work, so did Darth Vader. It was a major plot-point. Your probably also missed the point where the entire thing was an elaborate trap for the rebels and specifically Luke, so the shaft was obviously left open on purpose - there would be no reason to do that against the Federation.
You are either a god-damn idiot, willfully ignorant (in which case you are still an idiot) - or most likely both. You are clinging at your idiocy as a form of argument, even tough that's even more piss-poor than the rest of your mindless wank.
So - when they fight the operational DS-II, the Federation has to fight a heavily armored, heavily shielded battlestation with a diameter of 900 km and armed with more guns than the entire Alpha quadrant. They would have to defeat it within mere minutes, simply because the DS II can jump to hyperspace after that if it wants to.
Even with your wank-Numbers, simple scaling makes the DS II orders of magnitudes more powerful than the entirety of Starfleet - and all you get are, at best, parts of it, because your speed just sucks and you have your entire space to defend.
The second Death Star would utterly crush your pathetic Federation into tiny, bloody pieces, even if we grant you your made-up numbers. There is nothing they can do against it.