It's not meaningless because the behavior itself didn't change, only the scale. You can have one business that never changes their business strategy, but once they get too big suddenly they are anticompetitive without having actually changed their behavior.
This either says that either one believes behavior itself can never be anti-competitive (since it relies on scale as input), or that one must always take into account scale in the discussion. In which case, a lot of anticompetitive discussions need to add in a lot more qualifying context.