Why covered bridges are covered

In “Why are covered bridges covered ?” http://www.straightdope.com/classics/a5_174.html
Cecil writes “the somebody usually credited is Timothy Palmer, who built the prototypical American covered bridge in Philadelphia between 1800 and 1804.”

A somewhat slow moving Timmy, as the covered wooden bridge, spanning the Reuss River in Luzern, Switzerland, dates back to the 1330’s - or rather - dated, because it burnt down in the 1990’s - tough luck.

I hope you’re not suggesting that Unca Cece was… less than accurate. Please to note he said (as you quote), “the somebody usually credited”, not “that somebody was”.