The tone of this and Chris's post gives me the impression that it's harmful to include these query parameters, but I don't understand how. Could someone elucidate me? I understand it can mangle some URLs and that's good enough reason not do it, but even then it seems like a minor incovenience.
What's interesting is that none of these sites have a "search" feature. Which is an important accessibility feature and a clear and legitimate use case for a query string.
They aren't saying the concept of query strings are bad, They're saying unsolicited query strings during referal are the issue.