One of these bugs was literally causing servers to crash. We wouldn’t have stable servers today if they weren’t allowed to fix it.
On top of that, to come back on your example; of the 20 patches PoE had between 1.0.0 & 1.1.0, 14 had changes that either buffed enemies or nerfed players in some way or the other. I stopped counting after that, but if you want to, here’s a link to start: Patch Notes - Forum - Path of Exile
Or to put it in the words of someone else on these forums: