Buying links in order to 'cheat' your way to the top of Google's search page, thereby skewing the accuracy of their results, isn't fine.
I'd liken it to Ford paying 500,000 people to drive a Ford car and then claiming to be the #1 best selling car in the country. If they did that publicly it'd be ok (and compilers of car sales listings would ignore them). If they did it secretly then it really wouldn't. Tagging a link with 'nofollow' essentially makes it public that the link isn't trying to cheat the listings.
Buying links in order to 'cheat' your way to the top of Google's search page, thereby skewing the accuracy of their results, isn't fine.
I'd liken it to Ford paying 500,000 people to drive a Ford car and then claiming to be the #1 best selling car in the country. If they did that publicly it'd be ok (and compilers of car sales listings would ignore them). If they did it secretly then it really wouldn't. Tagging a link with 'nofollow' essentially makes it public that the link isn't trying to cheat the listings.