There's no link because the tweet was deleted soon afterward. The tweet seems to have been very ill-advised.
I don't know how anyone can describe this as a "bug", because as the linked article describes, there's an explicit "ContentFilterExclusionList" in the Info.plist file with a list of the specific Apple services excluded. That's not by accident, it's by design.
I don't think I'd call it a bug. It's a poor decision. I can easily believe that it wasn't a decision made with malicious intent; the culture at Apple seems (at least from the outside, judging by results) to encourage an "it's okay to give our own software special exceptions" mentality.
I don't know how anyone can describe this as a "bug", because as the linked article describes, there's an explicit "ContentFilterExclusionList" in the Info.plist file with a list of the specific Apple services excluded. That's not by accident, it's by design.