This is due to phishing attacks and account takeover attempts, not due to the platform itself being insecure.
They state that wire can be signed up with using an email instead of phone number, so it's less likely that someone will know the validation account used to sign up.
Feels to me like it's just a different attack vector. Maybe it's harder to do attacks on wire, but they didn't really say that in this article.
My gut says it's less attacked just cause it's less used, not that it's more secure. But I'm certainly willing to admit that I haven't looked into wire much.