Here is a credible link on the issue. You can view in i HTML form.
http://74.125.47.132/search?q=cache:leP ... clnk&gl=us
Essentially, it fully acknowledges the dangers (as do I). BUT, as the article states, the benefits outweigh the harm. This article further goes on to give parents instructions and directions to decide if their child is getting too little OR too much flouride.
What you miss, amongst all this, is that
everything --
literally EVERYTHING is "highly toxic" in large doses.
The second part you miss is that people in the past have had some pretty crazy ideas. Even if the article you posted is completely true in that the people concerned believed this, other evidence directly contradicts this.
Sadly, Google actually perpetuates many of these ideas. Because of how they constructed their search engine, ideas people find interested and controversial often appear much higher on their list than true, credible references. I click on flouride, and get maybe 15 studies that talk about how bad flouride is. I narrowed it down and finally found some articles that gave real evidence. So, you perhaps cannot be blamed for thinking this has credibility. Sadly, this is yet one more example of how poor science and critical thinking education is in our country.