Smooth apologies. I hold the same legitimacy for Aeon as well.
That's not really the issue. If people start going on about Aeon too much I squelch that too.
This is a Monero thread and very small coins just aren't relevant to Monero unless it is for some very specific reason (and sharing some of the same code isn't one). Maybe you weren't doing it deliberately but people form all coins are always trying to gain exposure for their favorite coin by injecting into other conversations, particularly conversations involving bigger coins with a larger audience and more investors. To keep this from turning into a shill-fest, its all considered off topic.
I agree that it might be useful to ban discussing any other coin by tacit contract to prevent the thread pollution, even when potentially relevant to Monero. I disagree that some cryptonote coins are irrelevant to xmr speculation, at least long-term, say ten years into the future. Perhaps we should start another thread confined to that topic.
There's nothing tacit. See the OP.
Off topic includes any extensive discussion of other coins, promoting other coins, or posting of promotional materials from other coins.
There is some subjectivity here, but "only legit other cryptonote coin" and given the tenuous at best relevance of a #600 coin, came off as promotion to me. Perhaps it wasn't intended as such, and indeed I didn't outright delete your post, just introduced a little speed bump on it.