I don't see how your example, The Browser (thebrowser.com), supports your argument that ad-hoc query-string additions are so prone-to-breaking that 3rd parties should ban them.
In fact, the example seems to suggest the opposite: a 17+ year successful paid subscription business – to which you appear to be a generally-satisfied customer! – receives enough "business value" from the practice, despite its failure modes, they don't want to stop. Improving their probe of the risk-of-failure was enough.
Seemingly, the practice works often enough, pleasing more destination sites than it angers, that "referral tracking" is not something "so minor".
In fact, the example seems to suggest the opposite: a 17+ year successful paid subscription business – to which you appear to be a generally-satisfied customer! – receives enough "business value" from the practice, despite its failure modes, they don't want to stop. Improving their probe of the risk-of-failure was enough.
Seemingly, the practice works often enough, pleasing more destination sites than it angers, that "referral tracking" is not something "so minor".