this is one of the few things i hate about them

Why I can't withdraw only "Available for withdrawal" funds and can't withdraw all my money from account?
Such funds holds because you have some earning from credit cards and PayPal account. Due to payment policy of most banks and PayPal system, they have apportunity to for chargeback funds for purchases made by credit card or Paypal. We hold such funds for 45 days to exclude our and partners incorrect earnings made by purchases and refunded lately to customers accounts. Also added hold period of 10 days for all purchases paid for via SMS, to reduce the amount of fraud.