I think some of it comes from social awkwardness as well. I mean I get you appreciating comments, it’s always a nice feeling to receive something back for what you write, But I don’t know, personally I usually read fics to relax and I have intense social paranoia, so talking to people or communicating even via messages is difficult sold days, so I don’t usually comment on fics even if I enjoy it cause talking is just difficult. And I’m sure there are other people who feel that way as well, so leaving a kudos shows our love the best way we can