On topic though I recently tried switching to FF and was surprised at how much slower pages were loading. Has anyone else experienced this? Is this just a matter of caching?
A) Everybody has heard of it (or can hear about it from somewhere else), B) nobody cares if a particular headline comports with it, because C) it's not a law, just a funny observation somebody made once that definitely doesn't hold anymore because headline writers are familiar with it, too.
Betteridge's law doesn't apply here because it answers the question: it comes down to privacy.
But even if it did, then Bettridge's law would apply. If you read the article, you will see that he doesn't say that Firefox is flat out better than Chrome. If fact, he even gives the performance advantage to Chrome and says that there are ways of "defanging" Chrome when it comes to privacy.
Really, the point of the article is not a technical comparison of browsers, but rather a statement of the importance of Firefox when it comes to privacy. And the value of not using a browser made by an adtech company.