On Reddit, Facebook, Instagram, Youtube, and basically everywhere but here 1 account = 1 vote.
Here, 1 account doesn't equal 1 vote. 1 Steem Power = 1 Vote.
If bernie has 1,000,000SP, it doesn't matter whether he has all his SP in 1 account or spread across 100 different accounts, he has the same amount of influence either way.
"he uses these account to up vote eachother"
Yes, he does. The end result is no different than him upvoting himself with just one account with the same amount of Steem Power.
I'm not commenting on whether it's okay or not - I could write an entire post on that topic.
What I'm saying is that if you vote for yourself from 100 accounts with 10,000SP each. It's the same result as voting for yourself from 1 account with 1,000,000SP.