I simply disagree with the game designers. As for the undead being evil, that's impossible, based on the principle that they're mindless. It's impossible to have an alignment if you don't think.
I think you probably understand that evil in the game is generally a force acting upon the world. Thus, artifacts, items, undead, and other mindless things can be evil, without regard to INTENT, which is usually the qualifier of evil for real human beings.
Acting cute and pretending you don't know that won't help you win your case, since it's been a given in the game since about... oh, say... 1974. Specific alignments of creatures may have changed over the years, but evil has always been a... thing on some level... not just a decision. But a force.
Now, if you don't WANT to play that way, that's fine. You're going to find yourself doing a lot of rewriting and revisioning. You might want to prepare a fully-edited PDF for your fellow players to study, since treating Evil as a non-force in the game world will affect a lot of rules. But it can be done. With work. With lots and lots of work.
But that's you choice, and you needn't dabble in trolling to make it. Just do it.
As to the question itself, if I choose to take it seriously, I think a lot of fun could be had playing a non-evil character dabbling in evil things and finding himself corrupted by it. It's an old trope, but a good one. I prefer to keep necromancy evil for my own games because then I don't have to do all that revisioning. And it's gross. And it's unnatural. But mostly, because when you create undead you are enslaving something. Whether it be a soul, spirit, body, whatever. You are enslaving helpless remains and possibly binding somebody's soul. That's pretty wicked.