Because it would appear that some people wish to remove all unsourced information. Unfortunately that results in stubs like this:
http://en.wikipedia.org/wiki/Cann_Quarry_Canal
That have wikicode that is pretty much impossible for a new editor to comprehend.
I've fixed that article. Adding footnotes to the same reference on each sentence is just stupid. Just putting the reference at the end is fine. Anyone that tries to claim something is unsourced without actually looking at the reference can just be ignored. If people checking for unsourced statements aren't going to actually look at sources, then they are going to miss statements which cite a source but aren't supported by the source, which is even worse than unsourced statements.