How can a "wrong" answer be voted as the "top/best answer" in Yahoo Answers?

All it takes is ONE vote. If YOU failed to "resolve" your question and just left it open for more then 4 days with NO reaction on your part, it's put up for "vote". That's the way it works.

It can be higher than nothing. Sadly, the downfall is that almost all voters do not learn by way of the solutions, they simply pick the primary or the longest. Excellent reply chosen as most thumbs-up, nevertheless, would still have its flaws. What if no answers have thumbs-up? Or more than one have a tie in the quantity of thumbs-up? Then how would it not be chosen? Having a vote, however imperfect, holds to the group facet of this web site, which I consider is important to keep.

It happens all the time when the asker doesn't choose and the question goes to voting best answer as voted is often not the best or even a correct answer. Naming another member as you have done is also a violation

Yahoo is NOT legally liable for wrong answers. It's as simple as that. LOOK at the bottom of the page for this statement

You can ***** all you want about other YA community members AND violate the community guidelines with your bitching UNTIL Yahoo suspends your email account for violating the CG too many times. The MORE you *****, the more Yahoo will suspend your email accounts, UNTIL YAHOO TERMINATES your ENTIRE email account for misusing the system to abuse OTHER YA community members. . .

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The Best Answer was chosen by users not by you. You have no control over what the Best Answer becomes, even if it is wrong, once you let the question go to voting. It doesn't matter if it is right or wrong it was chosen.

when it goes to a "vote" any answer can be selected as best answer

even if it is wrong

Anybody can vote, even the answerer for their own answer.

Yahoo has a disclaimer link at the bottom of the page, it reads in part "Yahoo! does not evaluate or guarantee the accuracy of any questions, answers or other posted information on Yahoo! Answers". In other words there's no guarantee that answers will be correct. Take all answers with a grain of salt until you can check out for yourself whether or not they are accurate.

When a question goes to vote, it's pretty much the asker's fault, they could have chosen the best answer themselves.

Mistakes can happen.