Well, the world of fiction does skip over that kind of fine-grained detail.
Literal
That's-true, fiction world [quot-ってのは] that-kind of detailed part [obj-を] skip [emph-からな].
そりゃ is the casual/spoken contraction of それは, used as a discourse marker meaning 'well / that's because / of course' — softening into agreement with an obvious point. ってのは (casual for というのは) marks the preceding noun as the topic 'what we call X / the thing that is X.' はしょる 'to cut short / skip over' is a casual verb for abbreviating or rushing past details, from 端折る (to fold the edge).