Well, you started with a strawman with "I'm upset because they are making the evil path more entertaining than the good path." so we're off to a bad start.
The argument people are making is closer to "An evil playthrough has entirely additional mechanics/systems that the good playthrough doesn't."
So how does the conversation continue if that is the first statement?
That extra "mechanic" is the one that offers power for sacrifice. It's not just a purely "evil" mechanic because it's the mechanic you must resist to call yourself good. But really what you are saying is precisely what JandK pointed out...you want access to the power upgrades of the evil path without sacrifice and consequence. You call it a mechanic while he called it a cake in his analogy...for the purposes of the game it is the same thing. You want access to the power upgrades that come from embracing a darker path without the sacrifice it requires so that you can have a meaningless good path where there is no consequence for giving in to temptation.