I can't see why Occam's razor wouldn't apply: don't postulate more entities than are necessary to explain the facts. Specifically, there is no reason to postulate some kind of anti-Firefox elements within Cloudflare when it's simply explainable as a mistake.

(There's a reason Hanlon's razor was given that name, I'm pretty sure, and that's because it's not too dissimilar from – essentially it's a much-more-situation-specific subset or variant of – Occam's razor. But I don't think "attribute to stupidity" was what the parent comment was suggesting.)