Earlier quoted context omitted.
Whataboutism is whataboutism. Attempting to invoke the thankfully largely-discarded concept of "whataboutism" is actually just a kind of backhanded ad hominem used to avoid making a real argument and instead try to make people "look the other way". Criticism of the existing financial system in the context of discussing a proposed replacement for it is about as related a discussion as possible. Simply stating that all…
Whataboutism is the derailment of discussion by roping in irrelevant subjects. Saying "that's off-topic" is not a personal attack.
You can question the relevance of a comparison without questioning the integrity of the person bringing it up: say it's off-topic and explain why.
More often than not, accusations of "whataboutery" are used to avoid having to explain why something isn't relevant and thus avoid addressing whatever point is being made. I'd go as far as to say it's why the word even exists.