Why does Northern Brewer's Fast Pitch Canned Wort not require any boiling?

Malt extract does not need to be boiled to make beer. It is perfectly possible to make beer using extract and cold water although it s a little easier if you dissolve the extract in boiling water first - just to make it more mobile and to pasteurise it if you feel it is needed. But just getting it hot to get out of the can and into the fermentation vessel is all that is needed. Once the Saccharomyces is fermenting well it forms a stable microbiome and (all things being equal) such a microbiome reduces the chance of infection from other sources. Sort of like penicillin mould keeps many bacteria at bay. Or used to....

Generally speaking water sources are chosen because they don't have contaminants. If one has to boil the water that one drinks then it will have to be boiled for any culinary use, including making beer. However fermentation (with saccharomyces or lactobacilius) is a method that can render water borne pathogens inactive and has probably been used as such for aeons.