While the use of quicklime by Bolivia was brutal, it was used as a last resort. Notice how they rolled boulders and burning logs before they resorted to using this devastating weapon. It is horrible that the Chilean soldiers suffered this, but the Bolivians held back on using it until it was necessary for their survival.
What I would like to call into question is the Chilean brutality against the local population in and around Arica. Killing men, women, and children who aren't even fighting regardless if they are from the enemy country is inhumane and sick.