I’m not sure what I feel about this if the original really is abandoned (is something ‘abandoned’ if it is working fine and just hasn’t been updated in eight months?) - but it definitely feels a little rich that the Redactle Unlimited author is complaining about copycats.
All of which makes it seem ethically-OK to me.
It's also relevant that the point of Redactle Unlimited was to offer a feature original-Redactle didn't, namely the ability to play more than one game per day. By making Redactle Unlimited, berjin made Redactle players' lives a little bit better.
Whereas, e.g., redactleunlimited.com credits neither original-Redactle nor original-RedactleUnlimited whose code I believe it has copied, nor does it offer any usability improvements or extra features over original-RedactleUnlimited. In other words, it's purely parasitic -- it doesn't on net make anyone's life better other than that of the person who "made" it -- and it's playing a zero-sum game, gaining whatever success it does at the expense of something that went before it, whose identity it's trying to create confusion with.
1) When I say abandoned the original redactle.com has had it's problems. There have been several days where the original was down because the hosting bill was not paid. Some fans tracked down the hosting company and paid it. Also the certificate was expired for months. Some days it loads a disambiguation wiki page instead of a real article. The dev hasn't been seen on social media since April.
2) Everything I did in redactle-unlimited is from scratch and with significant improvements like multi-player and lemma. The copycats are actually using others' content by either pulling en eBaum's world and embedding the sites or in one case cloning the source code, replacing the logo and domain and claiming to be the "official redactle unlimited" on reddit.
3) I'm hardly the only person to have re-created a Wordle or web game from scratch.