I think you're right on the word level but I think there's a difference about what significance and insignificance means to these groups.
As a religious person, I see my life as insignificant compared to Gd, and compared to the chain of generations, but what I do with my life is extremely significant. As in, whether I bring children into this world and raise them well, is massively significant.
So maybe the way to say it is - religious people see themselves as insignificant in the context of much greater significance.
The other view of insignificance is that nothing is significant - including myself. I don't subscribe to that.
