His reason, which has now been officially adopted into Amanda's Linguistical Code, is that Nice can mean so many different things that it really means nothing. Especially in writing, where there's no inflection or tone to indicate meaning.
By the way, I'm still looking for a publisher for Amanda's Linguistical Code, and please don't hesitate to contact me just because my book about language includes an un-word in its title. Part of my Linguistical Code is the acceptability--nay, the unrelenting excellence--of neologisms and sensical alterations to the language. (Like, for example, the use of the word 'sensical' because nonsensical is a word, so why in the world would sensical not be a word? That in itself is nonsensical. Oh, hey, I see what you did there. Good one.)
I'm a big fan of a subtly versatile word, but the word Nice means too many things. Allow me to demonstrate:
Today I had a nice golf game at a nice course with a nice friend, Alice. The weather was very nice, and I got some nice shots because of my nice clubs, and our skills were a nice match. We had a nice time at lunch, where the food was very nice. My friend spilled her drink on the nice tablecloth, though. They were nice about it, but geez--nice one, Alice! I gave the waiter a nice tip because his bum was quite nice, too.
See, it already means NOTHING to you, doesn't it?
Today I had a leisurely golf game at a picturesque course with a really kind friend, Alice. The weather was beautiful, and I got some impressive shots because of my well-crafted clubs, and our skills were a suitable match. We had a pleasant time at lunch, where the food was delicious. My friend spilled her drink on the elegant tablecloth, though. They were understanding about it, but geez--nice one, Alice!* I gave the waiter a generous tip because his bum was attractive, too.
*Some things, like idioms, don't change.
Isn't that more meaningful? I know--it's too overly describey, but at least all of the words MEAN SOMETHING. Of course, nobody would ever write the first paragraph, and hopefully, nobody would ever write the second one either, because it stinks in terms of readability and cohesion. But I think my point has been made, and so now I sign off and leave you with the same lesson that was impressed so indelibly on me so many years ago.
If you wince every time you accidentally say "Nice" for the rest of your life, well, I'm sorry. I shouldn't be passing out hammers from my bag.