Anytime a politician (or pundit) says “the fact of the matter is,” the next thing out of their mouth will at worst be a complete lie, and at best something remotely related to the truth but with a well thought out spin meant to promote their agenda.
In other words, there is indeed a “matter,” but whatever they’re about to say is definitely not a fact.
And BTW, the “matter” is usually a red herring designed to keep you distracted while their party takes something else from you while you’re not looking.
The thing is, they don’t really care if their little charade doesn’t fool everybody.
They just have to fool enough and let the tribe mentality take it from there.