I don't see how it would be a 'lame excuse'. It still shows that you suck, curse no curse. If you see it as an excuse, you're just as pathetic as the people that believe it is. Those are the same people that will scapegoat anything aside from the team itself. Illogical.
If that's your end all to why a team lost then yes. People have playfully used this curse narrative for years. Unless people are just complete idiots or don't know baseball, it's pretty clear there are many things you can blame individual players, managers, and a team for if they lose. Hell, this year if the Cubs lost, you could've found Maddon directly responsible with his horrid managing in games 6 and 7. The only people who would use a superstition as an end all for a team losing are the small minority of idiots that also probably think sports are completely rigged. There is no conspiracy.
Don't get me wrong...you guys were far and away the best team this year...and are set up for a very good future. With the money available to them and Theo Epstein, there's no reason why the cubs won't be good for a long time. I'm in the camp of there is no such thing as lovable losers...just losers. And I'm a die-hard Astros fan who just doesn't like the cubs.
The whole lovable losers mantra has been overplayed. It's all old talk from the 70s that has been pushed on and on as traditional things do in baseball. When you don't make the playoffs for 39 consecutive seasons, there's nothing lovable about that. So I agree. That's understandable. I'm satisfied with one championship. If there are any others to come, so be it. The Astros will probably get theirs soon with the future they have. Just a matter of time.