Explain NGE to a newb

So I caught the last 40 minutes or so of "Neon Genesis Evangelion Final" and am totally confused.

Why is Shinji strangling Asuka at the end?

Did anyone else think this was one big pretentious trying-to-be-art mindfuck rather than having some real underlying plot or message for the viewer to understand?

After reading about the creator of the series suffering from depression, the whole film really seemed like the expression of one crazy guy's screwed up mind. I'm sure it's meaningful to him, but to regular sane people it's meaningless.

Kopipe from another thread, because it's the same answer for the same question:

You can't really understand EoE unless you've seen the series.  It also helps if you know that Hideki Anno, writer of both the series and EoE, got a lot of hate mail for the way he ended the series, and most of the weird and depressing shit in EoE is Hideki Anno rubbing the fans' noses in it.

"Oh, did you like Shinji?  Did you respect him for struggling with his horrible and tragic life, his crippling clinical depression, then being able to fight heroically and save the day anyway?  POOF!  Now he fondles unconscious girls and masturbates on them, then tries to strangle them.

Oh, did you like Misato?  She dies horribly.  Did you hold out hope all this time that she and Shinji might have feelings for one another and be happy together?  POOF!  It's the world's most depressing kiss.

Oh, did you like Ritsuko?  POOF!  She loses her mind and goes insane, THEN dies horribly.

Asuka?  Torn apart by the Mass Production Evas.  Rei?  POOF!  She's the Angel of Death.  Maya?  POOF!  She's a puddle of orange goo.

Did you hold out hope for some kind of comprehensible hopeful ending, since Shinji has saved the world?  POOF!  The world is destroyed anyway.

Suck on THAT, fans.  I've got your happy ending right here."

NGE is one of the most impressive achievements in anime, one of the most impressive things I've ever seen.  But Gainax should have sent a few burly men to Anno's office after he finished writing episode 20, and given the project to someone else to finish.  It frustrates the hell out of me.  It could have been so much better than it was.