the thread was probably removed for not being a porn game. atlyss is out on Steam now for money and the itch.io/patreon builds are no longer being updated.
afaik atlyss was never a porn game, even back when it had its old name PoonQuest. it was adult and had nude characters with nipples but it was basically always about the gameplay. it was only mildly horny and was presented mostly for humor and sex appeal and nothing else. the very early prototype stages were never released publicly, only some PoonQuest builds were, and like I said they lacked any real adult content besides nudity. it's possible the story elements had some adult themes worked in, I don't know as I came into this whole thing late, but based on my research that I believe that also isn't the case.
for reference, ChuNipChu is a pikmin clone porn game prototype kiseff worked on around the same time where you fuck your pik(wo)mens to reproduce and spawn more. it's a barebones tech demo but does have sex. not really worth your time unless you want the historic preservation. you can find it if you search for it.
I don't know the context but kiseff decided to distance from porn and is now making the excuse that it was "for the commissions" which is bullshit. based on the incredibly spastic username changes and attempts to cover tracks in the past (nerlar == urielle == bunsnn == kiseff) I don't think they were ever proud of being horny and will not own up to it. look up those usernames on furarchive and you'll get the picture.
however kiseff is not against modding atlyss, since it doesn't compromise the vision he has of the game. there is a 18+ discord that adds some spice to the game but so far it isn't much. he has said previously he is fine with people adding adult content to the game, though those claims have since been removed from the FAQ on the itch.io page.