Because in this case he is specifically calling by the books jury trials "weaponization" and "lawfare." It's way beyond simple corruption, which he can do just fine with his various crypto and real estate scams, and the language is being chosen intentionally.

The pardon power is a constitutional one, but to disparage the entire criminal justice system like this is ripping the blindfold off Lady Justice in a plainly partisan and autocratic way. It's priming people for conditions which will ultimately undermine the process in both directions - letting him protect his allies and justify erosion of due process as somehow flawed or optional. He's already doing it with his deportation framework, in which people who have never been charged with any crime are being labeled "criminals" and denied due process.