Just for context, I also "knew" Armstrong was doping in 1999. As did anyone with a functioning brain and general understanding of cycling.
However, when I said "It's obvious he's doping" and "Yes, I do know he's doping" in online forums, I got flamed beyond all human belief by the idiots who wanted or needed to believe in him.
It was patently obvious he was doping. If someone in the sport had told me they had information that he was doping, I'd not have been surprised. However, I would also have had no evidence, and hardly would have announced it if I were a current or former pro cyclist, let along Greg LeMond.
When the link to Ferrari came out, voila, evidence, or at least possible evidence for what was already obvious. I would consider LeMond's comments very mild, and with the "way out" that he said "if it's true he's working with Ferrari".
I don't see why folks needed to construct the "he's jealous" narrative then, and whatever narrative is being created nearly 15 years later. Maybe he was jealous back then. To imagine that's why he commented (he was responding to a specific question) is a stretch for which there is no evidence, only opinion. Un-informed opinion at that.