I am the maintainer of Krita, I have spent ten years of my life working on that application. This person bad-mouths the work I did. When challenged to provide details, he then came up with exactly nothing, despite claiming to have scores more of examples ready. Heck, if this guy had come up with something interesting, I might even have acted on it. Now this Alex claims to have no interest in actually revisiting the issue. I find that extremely bad form, and yes, I take that personally.
I don't mind people criticizing my work. I don't mind people offering suggestions, reporting bugs, or even telling me Krita isn't suitable for their purpose. That's fine, Krita has a specific purpose and therefore isn't all things to all people. But I do despise people who piss on other people's work and then are too lazy or cowardly to back up their claims. I may be old-fashioned, but to me it means that everything else they say starts sounding like a lie, or trolling, to me.