Block users from creating issues

Hi, I am using to host a hobby project. It is open source, so everyone shall be able to contribute by merge request or by opening and commenting issues. However, I got in trouble with a troll, who is constantly opening useless issues with spam content. I reported him, but I cannot find a way to disable him from continuing his harassment.
Is there a way to block specific accounts from creating issues (because obviously I do not want to limit this capability to members only). And if not: Why not?