In this episode, the poachers were throwing a bunch of garbage and Poison-type shit into the local water source in order to pollute it and harm the local mons. Knowing that Suicune is a protector of the waterways and appears in order to purify water sources and provide fresh water to its territories and wildlife, they explicitly did some heinous actions to bait it out. They then ganged up with five or six Poison mons and poachers with nets to overwhelm Suicune and beat it into submission and capture into slavery.
Very different from a Trainer challenging a wild mon to a 1-on-1 battle and taking turns to hit each other, basically sparring as a training exercise, then capturing the Pokemon when it is weakened and tired in order to form a bond with, live happily/healthily together and respect one another as companions.
