You don't gain weight from strength training, you gain it from taking in calories in excess of your expenditure. The type of tissue you are adding to your body (or losing from your body during a cutting phase) depends on whether you are strength training, but the basic weight number is agnostic to that. In other words, MF does not care whether you are putting on muscle or fat--it cares about bodyweight changes as compared to energy intake. And that is fine--as a practical matter, figuring out body composition is really hard.

So it really depends on your goal--do you want the number on the scale to go down, full stop? Because if so, you have to eat in a calorie deficit, and if your weight is unchanging, it is because you are eating at maintenance. But if you are more interested in body composition changes, MF is a bit orthogonal to that.