これからEKって呼びますねっ！！((ネーミングセンスとは
ネットでこれを言われたんですけど、後半のインターネットスラングの意味はよくわからないです。「((」は大丈夫ですが、「とは」というのはどういう意味ですか？書き手の心情は一体何なんですか？自分がネーミングセンスないってこと？それとも僕がネーミングセンスないって？
これからEKって呼びますねっ！！((ネーミングセンスとは
Someone said this to me. I understand "((" is probably a punched face. But I don't quite get the 「とは」. My understanding is 「とは」at the end of the sentence can mean one of two things: short for 「とは何だ？」"What's the meaning of..." or short for 「とは思わなかった」.
This とは is a phrase used to present the definition (or important characteristics) of something (see Use of とは when there doesn't seem to be comparison). Another type of とは for surprise is not related to this sentence.
As net slang for ツッコミ, X + とは is said when some word or phrase is used in a strange and funny manner. It roughly means "Now I'm starting to wonder what X means...", "Is that what X is supposed to mean?", "What kind of X is it?", "Is that what you call X?", etc.
For example,
In your example, wasn't the word ネーミングセンス used proudly before this sentence? If not, that part probably means "Now I'm starting to doubt my sense for naming things" or maybe simply "What a sense of naming!". Basically they're saying they know EK is not a very nice nickname but could not think of a better one.
((is really a punched face... It's not something ordinary Japanese people recognize. It may be a mere typo. – naruto Jan 20 '21 at 23:45((used quite commonly on some sites/forums, often in the form of 「((圧」and 「((殴」. I was under the impression that those symbolized a punched face because of articles and discussions like this and this. I understand it is obviously slang and Internet speak in origin and is probably recognized by very few outside young demographics who frequent online forums. – Eddie Kal Jan 20 '21 at 23:56