urls Beginning with Question Mark do Not Trigger 404

It seems that any url that starts with a question mark redirects to the homepage of the site and does not return a 404

Example:
http://www.ameliasaltsman.com/?bad-link
vs
http://www.ameliasaltsman.com/bad-link

This is a real issue because our site was hacked. The hack was cleaned up but google will not remove the “This site may be hacked” warning because the old spam links are not returning a 404. They respond 200 OK and redirect to the homepage.

This topic came up several times in posts but I have not found an answer:

https://wordpress.org/support/topic/404-urls-with-question-mark-and-numbers-get-redirected-to-home-page
https://wordpress.org/support/topic/question-mark-url-return-200-not-404-string-query-noindex-or

Also here it is treated like something that should not cause a problem.
https://core.trac.wordpress.org/ticket/26878

Thanks very much
David