The "elbow pipes" etymology was proposed by the notorious fantasist Grattan Flood, and subsequently became "received wisdom", though there is little evidence to support it. Arguments continue to this day, but historians of the subject tend to favour "union pipes" as the original term. I haven't come across that political explanation before, I think, and I wouldn't know how much weight to attach to it; probably not very much, as it seems itself to be based on rather a lot of assumptions. The matter has been discussed in greater detail in previous threads.