Can't delete a route with 0.0.0.0 gateway

To delete a single route from a route table, you need to specify enough parameters so a unique match with one of the routes can be made.

If you want to delete a whole subnet (as opposed to a single host) you need to both use the -net flag and some indication of the scope of the network address, i.e. either the netmask parameter (e.g. 255.255.255.0) or a number like /24 (meaning that the first 24 bits are the network number, and the remaining 8 are used for hosts). In your case, both

sudo route del -net 192.168.76.0/24

and

sudo route del -net 192.168.76.0 netmask 255.255.255.0

would have worked.

(thanks to @nephente for useful additions)