you're wrong. Spit is just a direct damage ability. its comparable in nearly every way to Fireball (the closest similar ability) and comparable in many ways to other Direct Damage abilities like Snipe, Pounce, Hammer Slam, Penitence, Bite, etc.
getting hit by ANY 2 ABILITIES is bad news for you. do you really percieve there to be any fundamental difference between getting hit by a Fireball and a Spit vs. just 2 Spits? Just think about it.
if anything getting hit by 2 Spits is LESS SEVERE than 2 other direct damage abilities. you can cleanse them both at the same time with something like Rank 3 Heal or Oak's Shield. thats more than can be said about getting double Fireballed, which both deal their full damage instantly.