On one hand, Dell seems to think there is a market of people willing to pay to install Firefox. Whoever conducted that research probably found people trusting Firefox than IE or Chrome or Opera. That's just my guess. I have heard people saying "web download is broken. You first have to use some browser like Chrome or IE to install Firefox, but what if that IE version is compromised? What if people click on the wrong mozilla.org by googling and instead installed a malicious, modified Mozilla firefox?" Maybe Dell read HNs and thought "yeah let's help the poor souls out there!" (
http://noncombatant.org/2014/03/03/downloading-software-safe...)
On the other hand, this charging practice is ridiculous. I can understand some people are not technical at all (espeically the elders and new computer users), but come on, this is a ripe off. If you already created a custom image to load into every hard drive you sell to your customer, modify that image by adding Firefox. How much effort is that, Dell?
edit:
Does Dell's installation bundles with third-party addons? Remember the old toolbar spam? It would be interesting one day Dell decides to sell Tor installation service.