What evidence supports the link referenced being an advertisement? I'm not seeing any referral, tracking, or any URI parameter data at all that would support the claim, and this seems to be their only instance of referring to it — where, in this 'state of the union' helpdesk-style article, one or more such 'VPN provider' links seems particularly relevant to visitors. (I do not use whatever this company's products are and have no opinion either way on them aside from mistrusting the claim presented here.)
Amazon's `ref` parameter isn't used for affiliate codes. It's certainly used for something, but given that internal links have it (eg. the logo in the top left has `/ref=nav_logo`), I wouldn't immediately conclude it's an affiliate link just because it has ref. Actual affiliate links are through the `tag` parameter.