Very often, people post answers that are wrong, I hate that. Although this is not altogether avoidable, because of different levels of tech background, btu at least be nice not to answer questions that one is not familiar with.

You are correct: it is not uncommon for a thread to contain a reply that is not necessarily 100% correct. There are many reasons for this, and your statement highlighted one of them. In addition, the author may have misinterpreted the question or posted an answer after the OP updated the question. In general, replies are offered with the hope of being helpful to the OP. This site provides a place for people at any position along the Perl learning curve to ask questions and provide answers.

We encourage people to ask questions (after reading the appropriate documentation and using Super Search, of course), since PerlMonks would not be what it is without them. Similarly, we should encourage people to post answers. IMO, the richness of the site is derived in large part from the diversity of responses. Some replies may offer a snippet of code, some may suggest or explain an algorithm, some may provide a technical explanation that provides a glimmer into the guts of perl, some may provide links to previous threads or off-site resources, and some may touch on other areas. Responses are based on the authors' experiences and knowledge, and they do not all approach the same problem in the same way. Individually, each reply might not answer the question completely, but hopefully all replies taken together will address all of the important parts of the question.

IMO, even partially-correct replies have value. Such replies typically encourage a post from someone else, who gently corrects the errant information or points out a caveat that might have been overlooked. Occasionally such a post will initiate a spirited discussion that delves into a dusty corner of the language or uncovers a new quirk. Most of the time those subthreads go well beyond my understanding, but I still find them useful because it gives me another opportunity to learn. PerlMonks is about learning: by reading threads, asking questions, offering solutions, and every now and then by being corrected.

As an aside, and prompted by your reference to the "ugly thread about Oracle" in Re^2: To help not to misguide:

IMO, it is not the initial "incorrect" reply that makes that thread ugly, rather it is the insulting posts by Anonymous Monk that followed. There is a difference between correcting an errant statement and launching a personal attack on the author. The former helps to educate everyone that might have had the same (incorrect) thought as the author, but the latter only clutters up the thread with posts that contain no meaningful content.