Why do people need more reputation for EL&U for the same privileges than on some other SE sites?

Question

For instance, my 500+ reputation would allow me to cast close and open votes on a number of Stackexchange sites. Here, it requires 3000. Why is that?

Answer 1

Those sites are in beta and thus have relaxed rep requirements. ELU is graduated. Check out Math, another graduated site you're registered on — it, too, requires 3k rep to cast close and reopen votes.

For details, see the meta-Meta post "Reputation requirements compared", and the blog post "When Will My Site Graduate?".