They don't have solid evidence to disprove a lab leak. Disproving is a lot harder that proving.
I must concede that your statement wasn't blatantly false, but it uses weasel language to appear more truthful than it is.
I agree, but I don't trust any central authority (especially the government!) to do that for me.
Educating people & empowering them to make this call is a much more ethical, and fruitful, endeavor.
To loosely paraphrase Mark Twain (I believe?): Just because a toddler can't use a sharp knife doesn't mean that I have to use a butter knife to cut my steak.
That's a great quote, only we're the toddler. For all its political failings, the WHO is brutally more knowledgeable about the subject that us, and less biased than our local governments. They're asking China to open up so they can discard/prove a lab leak. If China refuses, the lab leak possibility remains on the table no matter its likelihood.
Weaseling the phrasing, one can give the impression that the WHO turned around and now thinks the lab leak is the most likely source, while they still consider the natural origin most likely.
There are no signs that it might be man made. There are no signs that it might have evolved in GoF research. But the WIV had a sample of a close ancestor of this virus, it's not crazy that someone got the bug and jumped out in that very same city.
So you may do selection on virions that target better certain receptors in certain human cells to infect them, and that's useful to know of possible evolutions of a wild virus, but in parallel it might be losing environmental resistance (temperature range, UV light), or maybe damage the expression of some vital protein, or become too pathogenic and die along with the host.
By all means, one could try to perform GoF in live humans to ensure there's no LoF, but that limits enourmously the speed of the research, plus it's usually forbidden to experiment in humans these days.