The premise of this article is incorrect. Google has banned gun sales via the Shopping tool since 2012 [1]. Archive.org doesn't have a capture from 2012, but there's one from March 2016 [2]. This is not a new policy.

A few people noticed that you could buy bump stocks and asked about this on Twitter; Danny Sullivan responded [3]. This has had some unintended consequences on wine sales... [4].

[1] http://www.thefirearmblog.com/blog/2012/06/28/google-shoppin... [2] https://web.archive.org/web/20160307053138/https://support.g... [3] https://twitter.com/dannysullivan/status/967521887914897408 [4] https://www.telegraph.co.uk/news/2018/02/27/wine-lovers-cann...