They may not be about to conquer space and then the world, or even grab any unusually valuable territory, but:

1. they are genuinely growing in capability at a rapid rate.
2. it would be better to overestimate them than underestimate them.
3. there's a sizable group of people who are more motivated by national competition than by anything else. It's not my reason to support space, but it gets support for space. And frankly, peaceful cooperation and "common heritage of mankind" blather isn't getting us anywhere.