The are happy to let you use their name, they just want you to pay for it. It's not just Ford, every big company does it - the logic is "I paid to make this a household name, or you wouldn't want to use it. Now you can help pay me for making it a household name." It is their right as a trademark holder.

I could argue for your side of it as well, because I tend to agree that the more their logo is around and the more we have pride in our Ford, the more trucks they are likely to sell. But, they make the choice...

 

Most likely payment is not an issue.... it's protection of their trademark. Look at Kleenex and Aspirin. They lost their trademark as they did not protect it. Once a company allows others to use the trademark and does not enforce it's right, they can loose it all together. Again, Ford needs to actively enforce it's trademark, otherwise it can be lost.