Photo number 6 on this website shows Sumter after the rebel bombardment. As you can see the damage was considerable, and the claim that Beauregard was trying to avoid casualties is, frankly, ridiculous.
I have no complaints, I'm merely pointing out what I believe was the southern point of view.
A point of view you clearly agree with. So I would suggest that their complaints are your complaints.
The most extensive and devastating damage to Sumter was in fact done repeatedly by Union guns in the years that followed, not CSA guns on April 12, 1861.
Again, I have no complaints. You of course, are free to indulge yourself in your own perceptions.
A little paint and some spackle will fix that up in no time!