Before anyone wants to be contrarian about this: no one is going to stop you from using a stranger's weeb digital art as your profile pic. It is not illegal to use someone else's art for your profile pic without permission and no one is saying it's should be.
The point of this post is that this is an extreme overreaction to a conversation that concludes with 'pwease ask this other person for permission, the art is of their character design not mine 🥺' in a niche art community that operates on an honor system for the sake of being polite to one another.
The real lesson is don't message artists on the internet unless you have an actual reason to.
Also stop using profile pictures. Let your username be your identity. Like in Smokey & The Bandit. All those truckers having cool radio handles like Bandit and Snowman. They weren't going "so, imagine like a generic anime girl with red hair and green eyes. A side-ponytail that's kinda' curly and a dainty smile represented by a single gentle curved line. That's a representation of my ego."
"I got a couple of hexbear smokeys here on the federated interstate. Churnin' up a fuss about something called a he/him lesbian? Whatever it is, steer clear of the thread. You'll know it when you see it. Massive pile-up up soy-ass comments and mod cops are chuckin' everyone in the modlog icebox."