Of course they can. People do stupid things every day.
What would you call it when people make assertions about things with which they have no experience and insist they are right?
But maybe I'm wrong, and you have direct experience. How about this...I'll show you a shot tracking something moving swiftly that I took with a ≥500mm supertele lens on a camera where I used the viewfinder held to my eye to track the subject, and you show me a shot tracking something moving swiftly with that you took with a ≥500mm supertele lens on a camera where you used the rear LCD to track the subject.
Here's mine, a snowy owl in flight taken with the R3 and 600/4L IS II:
View attachment 203620
I tracked the snowy from takeoff to landing, firing several 30 fps bursts over the few seconds of flight.
View attachment 203621
Now it's your turn.....