Most users simply do not read anything during installation and just click next, next and finish. Many of my friends and older members of family are like that, and they then call me to say that their PC is slow and browser pages took ages to open. I told them and also showed them countless times how to install software or some tool, proposed them to use Uncheky but no they want to do it their way.
AV software comes bundled, and some other good software recently started to bundle everything just to increase sales, users must understand that they must be cautious this days to avoid getting malware or PUP on their PC.