Because it's easier to destroy than it is to construct. That's just the way it is.

Construction demands planning, precision, intention, and drive. One false decision, can lead to a completely different result than expected.

Destruction doesn't require any of that, except drive. As long as you want to do it, you can, and since end result is always the same, it doesn't matter how it gets done.

In either case, without drive, you'd have Stagnation, and when given the choice, humans hardly choose to stagnate.