This is not the first article I've seen on an obsession that's recently hit the British press: men who sit in public spaces with their legs splayed far apart, taking up their neighbors' room.
Most of the discussion I've seen of this matter is far more dogmatic than the present article in insisting that it's a dominance issue, that the men do it deliberately to be aggressive and rude.
I was going to say that I'm sure that's not necessarily the case, because one of my brothers, the one who's now deceased, used to sit like that, and he was far from being a dominant or aggressive individual. He would sit with his legs splayed apart in the back seat of the car, with two of the others of us, who did not sit like that, trying to squeeze into the remaining space.
Because he was my brother, and my younger brother at that, I could address the matter directly in a way that London Tube passengers would be reluctant to do. I would reach over and grab his two knees, and pull them together. The other thing we would do was mock him. My other brother and I would splay our own legs apart, making electrical humming sounds as we did it, on the theory that some kind of high-voltage magnetic oppositional force was responsible for the reluctance of his knees to mutually associate.
Of course this annoyed my brother, as it was intended to do, but it didn't change the way he sat. He didn't spin any elaborate theories as to why it was necessary for men to sit like that. He was not one for elaborate theories about anything - I have another brother who specializes in that - and it wouldn't impress other males who didn't sit that way. All he would say was that this was how he most comfortably sat, so I'd guess he'd adhere to the male-pelvis theory, except that it was just his pelvis and not anyone else's.