Your node is synching the entire blockchain and validating the consensus rules...
GRS
- NBXplorer headers height: 5515096
- The node is synchronized (Height: 5515096)
LTC
- NBXplorer headers height: 2865547
- The node is synchronized (Height: 2865547)
- NBXplorer is synchronizing... (Height: 2537721)
BTC
- NBXplorer headers height: 888747
- The node is synchronized (Height: 888747)
BTG
- NBXplorer headers height: 887347
- The node is synchronized (Height: 887347)
MONA
- NBXplorer headers height: 3612765
- The node is synchronized (Height: 3612765)
DASH
- NBXplorer headers height: 1874916
- Node headers height: 1874916
- Validated blocks: 1874916
Watch this video to understand the importance of blockchain synchronization.
If you really don't want to synch and you are familiar with the command line, check FastSync.