Earlier quoted context omitted.
There was a ContentFilterExclusionList key in the /System/Library/Frameworks/NetworkExtension.framework/Versions/Current/Resources/Info.plist file. macOS 11.2 beta 2 removed the ContentFilterExclusionList. Does that take 6 months?
Noticing the issue, discussing it, setting meetings to agree to revert, and handling all other higher priority stuff before an eminent GM release and the most pressing x.1 update release, can take more than 6 months. Not to mention that "removing the ContentFilterExclusionList" is a hacky fix suggestion. Doesn't mean it's the actual hollistic fix, and there weren't other under the hood changes for this issue.
You've got in backwards. The ContentFilterExclusionList was itself a hack. It never should have existed.
Some people are handwaving about a mysterious vague problem that calls for a ContentFilterExclusionList, but Little Snitch has existed for many many years on the Mac and has been able to block everything, including Apple services. There was no problem with that until Apple decided to exempt itself from getting blocked.