This poll has always been a popularity contest (mostly of the internet fanbase in recent years) and nothing more. People who take this poll seriously have no idea of dance music at all.
Also Armin/Tiesto/whatever fanboys who blame Guetta's music for 'being cheesy' and 'selling out' are hilarious.
These are always garbage. I.e. Paul Oakenfold still in the top 100 & Boys noize being #100. Grats to Nero though, surprised they made the list but they deserve it.
These people at the top are barely even DJs at this point, but more a platform to sell their songs. They hawk their label's products and play really predictable sets to appeal to their mainstream fanbase. Some weeks there just aren't any good trance song released, but that doesn't stop armin from playing the same old tired sets. They aren't trying to make the perfect mix anymore, they just want to make as much money as possible before they get old.
So I don't really agree with the list, but as a popularity contest I think this is probably pretty accurate.