Microsoft specifically also stated that Linux "mutates" in anti-Linux advertisements, for example https://doraj.com/wp-images/2005/03/microsoft-vorteile.jpg

This fits pretty well with Microsoft calling Linux a "cancer".

(Note that you also have to carefully review licensing of libraries used with proprietary licenses; that's not a problem caused by open source unlike the quote wants to imply. Proprietary licenses also tend to "contamine" a project and make the entire project non-free, so that is not specific to open source either.)