>>424634 Those are super telephoto lens that cost several thousand dollars. I think if you can afford something like that, you are allowed to grab it any way you feel like. They might also be holding it that way to stabilize them. Note that a lot of them are on tripods so they don't have to be held from the bottom. Oh, and they also weight upwards 5 kilos.
Humanity one day needs to reach the point where we all have our heads encased in life-support helmets with digital monitors attached to them, and the only way we can show emotions and responses to situations is through our extensive personal collections of reaction images.