Also applies to the routing amounts. Nobody can tell you which amounts are forwarded and which aren't, unless node operators make it public. Spoiler: Most node operators don't do that.
Does anyone believe that messengers are confidential, just because they will not share their information with anyone?
What I'm saying is, that node operators only know about the routings of their own node. They don't know the origin and they don't know the destination of a transaction unless they started it themselve. Most of the node operators are completely unknown btw. So if somebody shares the info about the tx he was routing and how much fee he earned, you still don't know anything about the other nodes and you might never find out. Everybody is free to tell you how much Bitcoin he has, still many people won't tell you.
And this is a true statement. From this statement another true statement follows:
If node operators make their data public, then everything will be bad with privacy in LN.
No one can guarantee that node operators will not do this. You can only believe in it. But, as the English proverb says, "When three know it, all know it".
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They don't know the origin and they don't know the destination of a transaction unless they started it themselve.
Means, if a node operator makes his data public, he will only lose his own privacy. Just like everyone who makes his finances available to public, because he doesn't know where the money is coming from and where it went to. The english proverb you provided doesn't apply to lightning, because when three know it, only these three now it and the rest of the 12000 nodes doesn't know shit.
Why did you decide that only ONE node operator will give its data. Where there is one, there are 2, and 3, ... And here everything depends on the number.
Let's take the end users who will not keep the routed nodes. If one end user makes a transaction to another end user, then most likely 2 nodes (the sender node and the recipient node) are enough for the whole world to know about this transaction. And if we take into account that in the future, with a significant development of LN, there will be 98-99% of such end users,then the privacy of LN looks less convincing.