JECBrush: "The name is Brush, JECBrush. I enjoy ignoring other people and their words 99.9% of the time, with no sign of interest whatsoever. Why is it that I'm the way I am? Because I have no answer at all."
Some artists, on this site and on others, just like to post and share their art - sometimes in the hopes of gaining customers. They are not obligated to respond to every comment or message received. They do not have to make friends with every person they talk to.
Looking at their written posts, it looks like they've said they're not super active on this site anyway, so continuing to spam their profile makes it far less likely for them to want to reply and more likely to result in them blocking you for harassment.