A cheerleader is supposed to be energetic and enthusiastic, while someone on crack is erratic and out of control, so here the simile implies that the speaker tries to sound upbeat even though they are angry.
Context: "I try to sound upbeat even though I'm angry."
Hypothesis: I swallow the anger down and force my voice to come out like a cheerleader on crack.
Based on the context, is the hypothesis true, false, or unknown?