I think I just explained that in the prior note Linjo - and you didn't even have to scroll down to see it ;-) but I'll type it again here.
The top of the page says there is a one-stop pace for security issues, and provides a link called "visit security center". I clicked on that link. The place it goes does not provide for reporting security issues.
Secondly, there are no other links on that page at the top, so the message is pretty clear to push the other link to "visit security center" - to see the information you mention one must scroll down in the browser, but there is no reason to do so when the "one-stop shop" for security issues is given at the top with the link "visit security center"
I think that pretty clearly answers your question as to "how". I hope you aren't defending or involved in the development of that page. It is unmistakably misleading when there is no reason for it to be. Now that I'm here typing on this dialog, I've run out of time in my work day. Reporting the vulnerability will have to wait for tomorrow.