This raises a question though: does this company make something that users want? When a user installs a specific program is he/she looking to install other software as well? Is the argument that InstallMonetizer bundles useful software that it feels will enhance the user's life in some way? (going off the adage that the consumer does not really know what they want i.e. they'd just ask for a faster horse)
I recognise you are treading a fine line between defending a company you feel a duty to and practices and business model that you probably wouldn't select for Y-Combinator on the publicly visible business model. I hope they pivot to a less controversial model and leave you in a more comfortable place.
* You are right that the users are the advertisers but that must make the person running the installer the victim or at best the product.