That sounds marvellous in principle, but we both know that's not realistic. Also, what one person considers bitching and gossip, another person will simply see as discussion and debate.
I don't really follow much entertainment news, but I think if you're in the public eye then you have to accept that gossip and speculation is going to be inevitable.
I also believe in freedom of speech, even when it doesn't agree with my opinion.
For example, I'm well aware you're an avid Sussex supporter and have voiced a dislike for Catherine and the Royal Family previously. And that's fine. It's entirely your right to do so, no matter how vehemently I might disagree with your interpretation. I think it would be really wrong to suggest that you can't share your opinions in a suitable space. I would always champion your right to be able to discuss, debate, and criticise the royal family however you see fit.
However, my objection to unpleasantness on this thread is twofold.
Firstly, the OP explicitly asked for this to be a thread about positivity. There has been similar requests on threads about Meghan which you have been in support of. I don't think it's unreasonable to ask people to stick to the subject on any thread - that includes threads about Meghan. Again, regardless of whether I agree with the OP or not, it's a reasonable request at any time - but particularly at the moment for Catherine given her circumstances. Which brings me onto the next objection.
A woman with a young family has just announced that she's been diagnosed with cancer. I think that continuing to pile into her publicly shows a real unpleasantness. People are really affected by this, not just because of Catherine, but because cancer has blighted many lives, in many ways. Right now, when her cancer has just been announced, can you really not refrain from being nasty? Especially when it's totally unrelated to the actual thread. There's absolutely no need to visit a thread that is asking for positivity about Catherine, knowing that you don't particularly like the woman, just to add spiteful comments.
Surely at some point a line is drawn where you think, yeah, maybe now isn't the time for this? Because I think that time is right now, on this thread.
I don't think it's hypocritical to recognise when online criticism steps over a line. I don't think it's hypocritical to recognise that you don't always need to share your opinion when clearly your opinions aren't in keeping with the spirit of the thread.
It's like joining a thread about lemon cake recipes just to keep posting comments about how much you don't like lemon cake.
If you really are busting with the need to rip into Catherine and can't refrain from being critical, just this once, then go and put up your own thread about her.