“Uncontacted”, in this instance, is more like “They’re talking to other indigenous folks in the vicinity once every couple of years and it is generally known that they want to be left alone so Peru doesn’t insist on issuing everyone ID cards and considers them sovereign regarding criminal law and stuff”.
They’re already resistant against the usual bugs and as far as illegal loggers, poachers etc. are concerned: Those don’t give a rat’s arse about whether a tribe wants to be left alone or not. Or whether whoever they come across is indigenous or not.