If it makes you all feel any better, think of the people, the ordinary portoguese supporters; Portugal never won anything, and back in 2004 they reached the finals in their home tournament and LOST. At least a joy for a nation that didn't really have any so far, for France it stings but they know what it's like to win the Euro Cup and the World Cup.
The other reason I rooted for Portugal is that I always root against the host country of any tournament.
Yeah, isn't it rude to host a tournament and then win it? it's like throwing a party at your house and being the one who enjoys it the most, it shouldn't be that way!
I'm always out for some drama in football when I'm not personally involved, so rooting against the hosts falls into that category. More generally, I remember being undecided about the Bayern Munich vs Borussia Dortmund Champions League final, then when Bayern scored I started to root for Borussia 'cause I wanted to live the drama of Bayern being catched up with the victory at hand. Seeing the hosts losing falls under this category, when you're not personally involved it's funnier when the stakes are very high.
I think this tournament was more about the favoured teams not getting their shit together at the right time than Portugal actually deserving to win this. But anyway, that's life.
Well, that's the point of the Euro and World cups... it's not a season long tournament when you face everyone and the best one usually comes out, it's a tournament where you have to be on top form for just a month, and then play at max 7 matches when half of them - especially in the World Cup - may be against significantly lesser opponents.
Also in these situations the national feel helps to cement a team, it's easier to keep together for a month a bunch of people of the same nation (Italian CT Antonio Conte was great at this) than holding together for a whole seasons players in a club from different nations.