That tool is particularly bad as it somehow decides that underware is similar enough to underwear that it should map the word to the word for underpants in my language. The rest of the page is a little better, but not by much. But the problem here isn't the quality of tool itself which results in particularly amusing choice of words but by the use of the tool itself.
Don't do that. If the end user wants to read your page in a different language, they are perfectly capable of clicking that button in their web browser and deal with the outcome themselves.
Just don't. I will not hunt down the language selection button on your badly translated web site and I will not change my web browser settings for your site alone. I will simply choose not to visit your web site, and I suspect many others will do the same.
(I wonder why people would even do that, since as you say, all the modern web browsers have built-in support for a translation button.)
Strange enough, the description has a hint about the translation, and I even can turn it off to get the English original, but this is not working on the Headline or the website itself.