FYI, it stops looking like innocent questioning when you put more time and effort into repeating the question in multiple places than into looking up the answer yourself. If you think someone is wrong, then be forthright about that, and consider whether addressing the lack of adequate sourcing is still necessary after you've made a real contribution to the conversation. In a topic like this one, people can reasonably make very different assumptions about what is "common knowledge" that doesn't need full citations every time it's mentioned.
The GGP is neither a credible source (it's an unsupported statement by an internet rando) nor speculation that withstands much scrutiny (IIRC, circa 2014, Ukraine had blocked the channel that supplies water to Crimea, and that didn't cause the Russians to abandon it then, and I don't see why now would be any different).
There's a lot of wishful thinking and propaganda swirling around this conflict, and strong claims need strong evidence.
I'd say any claim needs evidence (with some extreme exceptions), and in fact it's only the evidence that's worth reading, not the claim.
Rando claims have zero value by themselves - there is an infinite supply that say anything and everything. That's why science, law, etc. require evidence.
I'm a little confused: You did not provide any source. You're not obligated to provide any, but I don't understand your comment.