I very much doubt that a defense and indemnity clause, with no signature attached, would hold up in court to the point where a Pinterest user would actually pay

I very much doubt that a defense and indemnity clause, with no signature attached, would hold up in court to the point where a Pinterest user would actually pay to defend Pinterest. With that said, the only real way to fight back against crazy EULAs is to stop using services that have them. With that said, pick your battles. I'm not a Pinterest user but this EULA wouldn't stop me.