Muramasafags really are deluded
The only people that pretend to like him are the ones that ship him with castoria because "omg FSN Shirou and saber reunited again in another world". No one actually likes him as a character other than the people that massively project Shirou on him and project Fate route saber onto castoria. He's not a character outside of clap service.

There are polls of the most popular male FGO characters, Muramasa really isn't that high up.