The top 5 likes to list shitcoin and hypecoin a lot and as it happens the market also like it. That's why they got huge trading volume.
The rest aren't too fixated on listing shitcoin so they may have lower trading volume but they're as reliable as the top 5 if you can determine their credibility not based on volume alone but when those exchange are founded and the fact that they're still standing till this day.