That said, I do agree that bit of advice is ill advised. Call the police, they're trained for this stuff.
And hopefully you'll never have to use your weapons.
I'm all for gun rights, but this strikes me as a super weird thing to say.
It's like saying "Good news, in the US at least, all cars have safety features. Seat belts, especially, save lives. So, there's that stopping oncoming traffic from harming you and them if you drive at full speed going the wrong direction on the interstate."
An assailant with a gun is prepared to do you harm. There is a 100% chance that they are going to have their gun with them and be ready. They are no more going to wait for you to prepare to defend yourself than the person with a knife is going to swing it widely in a way your corner self defense class is going to prepare you to defend yourself.
That’s like people saying they want guns to protect themselves from the federal government when a small town SWAT team could take them out without breaking a sweat. Let alone the federal government with the worlds largest military.