Which can be argued to be not true. Yes you do not activly offer a service to other users that do not have a full node, but you still verify and help broadcast every transaction that is passing your node as well as every block.
If you check the peers tab you can click on a specific node and it will show more information to the right. You will see "Starting height" which should be higher for all nodes than your "current number of blocks" (information tab). If thats not the case you are connected to peers that are not fully snyced as well.
If the peers you are connected to are fully synced, but only deliver a few KB/s they might have a bad connection or are otherwise bussy. If this problems remains over night I suggest you manually connect to a node with a good connection. I used to take care of a list of nodes, but all of them are currently not reachable. You can find active nodes here -> https://getaddr.bitnodes.io/nodes/?q=/Satoshi:0.11.0/
You can connect to a single specific node by starting bitcoin core with -connect=IP or to several (up to 8 ) nodes by starting with -connect=IP1,IP2,IP3,...,IP8. Make sure to fully shut it down first.