Portugal's attitude in that match was that they wanted to fulfill two goals:
1) Score points against the All Blacks.
2) Avoid losing by 100 points
They scored 13 points and only lost by 95, earnt the respect of the All Blacks, beat them in football that evening and even managed to have one tactic that still left Graham Henry confused four years later. It was treated like a win and 10,000 people turned up at the airport to welcome the team home. Most crucially, a similar number of children started playing rugby in the next few months.
The problem they faced is that the 2007 squad were reaching the end of their generation and there weren't the players of the right quality to back it up, leading to a decline in results from 2009 to 2019, however things have changed since then. The generation of kids introduced to the sport started to reach an age where they could play at U20 level, a they are an extremely talented group.
From 2017 onwards, Portugal have comfortably been the best U20 sides outside of the 6 Nations and Georgia, coming close to qualifying for the World Rugby U20 Championship. Had it not been for Covid cancelling 2020 and 2021 I'd feel confident Portugal would be in the senior U20 competition this year. The 2017/18 generation are now braking into the national side who are performing as well as any Portuguese side has done for 10+ years.
No nation will go from losing every match to contending for a Rugby World Cup overnight. It'll take 30-50 years before a nation like Portugal can produce a stream of world class players. If you deprive Tier 2 and Tier 3 nations of all matches against Tier 1 nations it simply won't happen.
So going back to that match 13+ years ago, whilst you saw a 108-13 thrashing, Portugal's players saw it as mission accomplished. The players became heroes and inspired a generation, which if given the opportunity will inspire the next generation to even better things.