I'm sorry you are so disappointed, but honestly I think you're WAY overthinking it. Most people don't even get the luxury to read their recommendations. I've waved the right to read them (which I think is generally the correct thing to do) so when my recommendations come in I won't even get to see them. As long as recommenders have good things to say, that's all that matters. If they miss a question or two, have some spelling mistakes, don't put it in the right format, etc... it does NOT reflect poorly on you in the least. Only if they speak poorly about you, would it look negative. They understand that recommenders are busy, not professional writers, and that they're doing you a favor.
PLUS, he asked to have the letter removed, so it is my prediction that they won't even get a copy of the orignal letter. I'm telling you, think about it. They've seen everything else in your application and really like you, then they take a look at one rec letter and DING you? No way... A ding will never be on the basis of a recommendation only, UNLESS the recommender had nothing but bad things to say about you.
Consider yourself lucky that you got to see a copy of it in the first place, and move past it. It's easy to blow up something like this and feel that it will define you. But read around the forums and see all the people that got into school with mistakes in their essays. I've seen multiple instances where they put the WRONG NAME OF THE SCHOOL they were applying to, and they still got in. Adcoms are not looking at the details, they're looking at the whole package. Keep your head up ok? Take a deep breath, and think about how you're going to ace your interview when it comes around. You got this.
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