I am watching a live stream of Roger Ver talking about Bitcoin. Yes, I know that a lot of people violently hate him and I will say that I don't like Bitcoin Cash. I sold all mine for Bitcoin very early on, and it seems to me that bigger block sizes are a bad thing.

However, I must admit that many things that he said then and says now seem to make sense. I'm very open to the possibility that he's lying or warping the truth, but this in particular is something which stuck out to me:

Basically, he is saying that Bitcoin has been fundamentally broken on purpose by introducing the "replace-by-fee" feature, which, according to him, allows you to "reverse" (take back) Bitcoin transactions for minutes, hours and "sometimes even weeks" after it was sent.

Is there any truth to this? Is he purely making this up to cause fear and doubt? If so, please give me all the details.

My understanding of the feature is that it simply allows you to "unstuck" a stuck-in-memory-pool transaction by essentially throwing it a few more satoshis for the transaction fee, so that it will not be ignored but rather included quicker by the miners while a lot of Bitcoin transactions are happening at the same time.

Please let him be lying. Another thing that makes me doubt myself and my own understanding of the whole situation is what he says about the Lighting Network, which I agree is "ultra-complex" and "never seems to come into actual use".