Isn't the whole point of firearms that you
don't have to be built like the hulk?
If you're strong enough to pull a trigger and generally ambulant that should suffice.
It may not be about fighting off attackers.
Imagine if this was a school campus or a kids baseball game as you're pulling up in the parking lot.
Raw bodycam from the shooting at the Allen Premium Outlets mall:
Allen, TX Bodycam Warning: Video is blurred out. But it's pretty intense.
Having a firearm and knowing how to use it is a good start, but don't you want every advantage you can get?