I've been eating sardines since like 3rd grade. My dad bought me some nice ones in olive oil, I liked them and bought them to lunch and everyone freaked out. I was unaware why.
I dunno, the whole "aww the animals" thing was lost on me. I had outdoor cats and everyday I'd see them kill birds and squirrels and whatnot and tear them up in front of me. So I can go to the Asian market and buy whole fish with heads on and butcher them myself and everyone, again, freaks out.
Personally for cheap sardines, best are sardines in hot sauce. But mackerel kinda just tastes like a big sardine for cheaper (not as good, though, I think sardines are fattier.)
Also sardine/mackeral are no big deal, especially when canned they're soft. I get much more mad when I bite chicken cartilige or something.