I don't know man, mass replying to a handful of negative comments like that really doesn't scream "confidence" to me.
I just don't suffer stupidity. If I actually make a mistake, (spelling mistakes, grammatical errors, etc.) I own up to it straight away. The problem is I don't think I made a mistake- I've explained my reasoning, in detail and still have people saying "Uh, NO. Slang bad." (essentially) and I'm defending my decision.
Part of the point is that if you know Japanese and see デッ!, you instinctively know it's just a shortened version of the full word. "Gyatt" is just gibberish to anyone who doesn't live in primarily English speaking country and engages with the youth culture
"Gyatt" is the shortened version of "Goddamn". Do you take issue with the word "gonna" (or further, "gon'" being used in place of "going to"? Because that's exactly how your argument sounds to me. Japanese have dozens, hundreds even, of example of full words shortened down to just two or three syllables by primarily the youth cultuer (I instantly remember a discussion about the use of "マ?" among the youth as opposed to the more formal "本当に?") The same applies here with "gyatt", he's a young guy, shown to be flamboyant and uses casual, somewhat meme-y language before and in this case he used a single syllable from a longer word to express surprise/arousal(?). As to the doesn't make sense to those who don't live in primarily English-speaking countries.... well, I'm translating it into English for an English-speaking demographic, that kinda isn't my problem?
these two don't seem like words to me, they're more like fads. In a year or two no one will know what the hell they mean.
I think you're letting your personal opinions on neologisms get in the way. It doesn't matter how you personally feel about a word in colloquial use, the fact of the matter is that it's in use by the same demographic that Kuzutani is in (if he were English-speaker) so I use the words and manner of speaking that he would use if he were an English speaker, as close to the essence of the words being used in the raws.
I don't mind having the conversation about the use of slang, dialects, etc. in translations but I don't like having people making assumptions about me nor saying they wish bad things upon me for using slang that they personally disagree with.
Very often, I've given my detailed reasoning as to why I used those two words and asked "Well, how would you have translated it any better to get the same meaning and comedic impact across?" and they just go silent, I have yet to receive an actual answer which only proves to me that I'm right, in my mind at least.