Relevant Brave (Chromium-based browser) bug discussion on exactly this:
https://github.com/brave/brave-browser/issues/1127
They merged in a (partial?) bug fix in 2019:
https://github.com/brave/brave-ios/pull/883
The underlying problem isn't that Google sites are directly excluded, it is that Local Storage, Database Storage, and Service Workers aren't cleared by that setting, and that Google uses those for persistence.
Is this being evil or was support just not added when those were introduced? I have absolutely no idea. But I agree with fixing the underlying bug in Chromium either way.