Well in all honesty, Rainbow Dash wasn't exactly loyal either. Had Twilight not stepped in, she more than likely would've left her own team.

Plus RD is boastful and arrogant too, we can't just pretend those aren't core parts of her character.

It certainly puts past Wonderbolts episodes in a whole new light… Soarin' seemed a bit dorky (and pie-obsessed) in Grand Galloping Gala, now we find out he's a putz who's looked down upon by his teammates. And now it's a possibility that Spitfire genuinely thought the win-at-all-costs Lightning Dust was a better recruit than Rainbow Dash, and only threw her under the bus because her recklessness caused a near-fatal accident…