Well this all sounds silly. There are literally thousands of adult artists on the web and they go after you for chibis? Sounds like you're getting bullied. Even if you were producing straight up hentai, what's the point in getting upset about it? Drawings are a non-violent means for people to express ideas and feelings with, your trolls sound like dip-sticks.
CIEIRMusic
Personally I don't think it's necessary as you know your stuff as it's your stuff, however that said if it gets them to back off, more power to you.
That being said, when you mentioned it, it does raise a point. Over the years, I've watched many a cartoon and anime. A lot of characters despite their looks otherwise, often have varying ages.
The big examples being:
Yugi Muto who is 17 - 18, yet looks like he's 10. Which has been a running gag both in and out of the original Manga and Anime.
Satoshi aka Ash Ketchum who up until the Alola episodes was perpetually 10 years old despite looking like a teenager.
The Sailor Scouts. Whom despite looking like their late teens started out as 14 years old. Making a few transformation scenes very questionable outside of Japan.
Even Newgrounds is no exception. Despite his small South Park like size, Pico when he started was around 16-17 years old and is 19 - 20 around the time FNF came about.
Chibi characters that are older than they look at this point really shouldn't be complained about by those looking for an excuse to hate and cancel you.