On one hand, this is a scummy move from CloudFlare. All this has ever done is make browsers spoof their UAs. Mozilla/4.0 anyone?
On the other, Pale Moon is an ancient (pre-quantum) volunteer-supported fork of Firefox, with boatloads of known and unfixed security bugs - some fixes might be getting merged from upstream, but for real, the codebases diverged almost a decade ago. You might as well be using IE 11.