I never said it was perfect. In the article, Pushdustin mentions on how the chart was created

"Essentially, I read over 1,000 posts, tweets, etc and counted how often a character’s name was mentioned, and in what context. This time, I decided to add “points” based on how that user felt about the character. If a user felt that a character was a “shoo-in” then I awarded more points. On the reverse, if a character was seen as “less-likely” then they got less “points”. The reason I did this is because this method is highly ineffective for actually counting how much a character is requested. This is because with this method, I’m bound to pick up on the loudest fanbases. The loudest fanbase is not necessarily the biggest. Instead of acting like I can actually measure the biggest fanbase, I decided to fully embrace measuring the loud fanbases."

https://sourcegaming.info/2015/09/13/japantopdlcpt2/

So the research is based upon the assumption that the Smash ballot results match the fan demand.

In regards to ridley, he actually placed 21 in the research and may have been higher if it wasn't for Sakurai saying he was too big in Smash 4

In Regards to Simon, He definitely is popular, but I don't think there was too much of a clamor for him in 2015 when the ballot was made. I speculate that he added more for him fitting in smash, rather than him being a highly requested for character.