I have installed and removed MacKeeper and can definitely say that what Thomas has written is false.
No you can't, all you can say is that your one single test gave different results.
I will admit that I have not installed, and will not install, MacKeeper. After keeping an eye on the company behind it (Zeobit) for some time, I wouldn't trust it on my machine. (Which is ironic, because I actually did install some variants of the MacDefender malware.)
However, neither does that mean that my claims that MacKeeper left bits behind are false, just because I did not personally observe them. I trust that the back side of the moon exists, even though I have not personally seen that. In order to criticize my information, you must first know more about it, but you have not bothered to do that.
In general, I would agree that basing information solely on a few reports here is not good practice. However, there have been more than a few reports of MacKeeper pop-ups appearing after it is removed here. In addition, I have had a number of private correspondences with people who have told the same story. And this was before I said anything about that on my blog.
I have absolutely no doubts that this was actually happening, based on the number of reports I saw. (Most of which you were not privvy to.) However, I should also note that I have seen absolutely no reports of this behavior lately. So, it is entirely possible that Zeobit removed this behavior once it started having attention drawn to it. That would fit their typical pattern of behavior. For example, a number of people called them out publicly on the fact that they bought the clamxav.org domain and put download links for MacKeeper all over it. Since then, they not only hid the site's ownership behind a service specifically meant for obfuscating that information, they also eventually removed all references to MacKeeper. (The site still remains, however.)
In other words, etresoft, all you really know is that you tested it once and, at that time, it did not display that behavior. To extrapolate from that that my claims are false, especially when you have absolutely no idea what data I am basing my claims on, is not logically sound. But then, your arguments have never suffered from an excess of logic or soundness, so that does not surprise me.