alt Hacker NewsA simple ruleset would only block a couple dangerous ports and leave everything else connectable. Whitelisting outgoing destination ports is more complicated and more annoying to deal with for no benefit. The only place you should be whitelisting destination ports is when you're looking at incoming connections.
I definitely block outgoing ports on all our servers by default; Established connections, HTTP(S), DNS, NTP, plus infra-specific rules. There is really no legitimate reason to connect to anything else. The benefit is defence against exfiltration.