A good question, well that is because in the world there are different types of people, people who are intelligent and people who are not, people who understand and people who do not understand the dire consequences of their actions. Many fans are quite Hormonal and very Jumpy so whenever they see a person who looks like their fave character from an anime they find a "My Kokoro goes Doki Doki" material or a real life person who they can fantasize about. Unfortunately Mr. Yuzuru was their target this time, sometimes people go with it and sometimes it just annoys the F out of people and in this situation it was the latter. Being a Yuuri Katuki I mean Katsuki fan I hate the fact that my precious smol katsudon is being compared to any skater, dead or alive. Well if Yuzuru really had anything in common with Yuuri then it would be up for debate but the only thing similar is that they are skaters and that's it. Period. If you think that Mr. Hanyu looks like "The Japanese Sleeping Beauty" etc.etc. etc. then you seriously need to visit an optometrist because you are delusional AF. Also Do not forget the fact that Real Life people can never ever be compared to Anime characters because they are just Out of this world, wow and amazing to the power of infinity. If you really want to compare real life people with Anime characters then cosplayers are there for you, they are 100% willing to be your real life human fantasy (Hana from Baozi&Hana is great as Yuuri Katuki ;) So my friendly advice, if you see any more comparisons and BS anywhere just delete it and be the Bigger Man and ignore it ^-^
Have you ever seen one of Yuzu's programs? They are really great and you should check them out. He is a really awesome skater and won a gold medal in the Olympics. He is also Japanese, and is an inspiration for YOI.
If I'm honest, if Yuuri is based off of anyone it's Tatsuki Machida. It's even mentioned on his wikipedia page. He has incredible artistry with balletic movements, great footwork and tight spins. He just struggles with jumps. Not to mention he is known for wearing make up and expressing gender fluidity in performance. Look him up.