I am a licensed piercer, and mall piercing kiosks especially for young children are absolutely deplorable. The people who do it are rarely licensed (or certified) most training takes less than two weeks.
The actual conditions are terrible and few wear gloves. It's impossible to sterilize a piercing gun even in an autoclave. Plus they only rub it down with alcohol. No one is trained in dealing with blood borne pathogens or even infection control. It also causes trauma to the tissue in the ear.
I don't even want to get started on the cartilage piercings in the mall (which with a gun it can literally shatter all the cartilage).
I personally don't believe infants should have their ears pierced either (especially at a mall) because not only are they unable to communicate if something feels wrong or otherwise.
I know in some places it is a cultural thing, where they do it as soon as the child is born.